J1225.0+2146 This source is double-lobed, with an extended K-band ID towards J1225.0+2146 the western lobe. There are two plausible candidates for the ID, J1225.0+2146 which may be interacting, at RA=12:25:02.40, DE=21:46:52.6 J1225.0+2146 with K=20.12, and RA=12:25:02.51, DE=21:46:54.5 with K=20.20. The J1225.0+2146 entry in Table 2 is the magnitude for the westernmost ID. There J1225.0+2146 is also a faint infrared source at the centre of the western lobe J1225.0+2146 (RA=12:25:02.14, DE=21:46:50.6), with a K-band magnitude K>21; J1225.0+2146 this is unlikely to be the ID but could be enhanced emission due J1225.0+2146 to the passage of the radio jet. J1226.3+2418 This is a large radio source with a secure ID at the centre of the J1226.3+2418 brightest radio emission. J1228.9+3114 This source has a slightly extended radio morphology centred at J1228.9+3114 RA=12:28:59.58, DE=+31:14:57.6. There is a bright K-band J1228.9+3114 counterpart to the north-east of this centroid at RA=12:28:59.56, J1228.9+3114 DE=+31:15:01.1, which may be the host galaxy. However, this is J1228.9+3114 not centred on the bright radio emission, and it is possible that J1228.9+3114 a true ID centred on the radio emission may be beyond the J1228.9+3114 detection limit of our imaging observations at K>20.7 in a J1228.9+3114 3-arcsec aperture (3{sigma}). J1229.1+3040 This source is slightly extended in the radio map. We have a total J1229.1+3040 of 3240s integration with UKIRT on this source with no apparent J1229.1+3040 ID down to a limiting 3{sigma} total magnitude of K=20.7 in a J1229.1+3040 3-arcsec aperture. J1229.9+3712 The radio morphology for this source is such that it could be the J1229.9+3712 lobe of a larger source. Indeed, inspection of the FIRST radio J1229.9+3712 maps does show three aligned components with a probable core at J1229.9+3712 RA=12:30:02.98, DE=37:12:46.1. The full extent of this radio J1229.9+3712 source on the sky is ~3 arcmin. The FIRST radio map overplotted J1229.9+3712 on the Digitized Sky Survey R-band image is shown in Fig. 2. J1229.9+3712 There is no bright ID detected in the POSS-II image at the J1229.9+3712 position of the core. J1230.2+2326 This source has a double-lobed radio morphology with a bright J1230.2+2326 K-band ID situated between them, along the radio axis. J1230.6+3247 This is an extended radio source with two K-band counterparts J1230.6+3247 close to both of the bright radio components. This could be two J1230.6+3247 distinct sources with both of the two infrared objects hosting J1230.6+3247 an AGN (marked A and B in Fig. 1). We note that the peak centroid J1230.6+3247 of the 74-MHz radio map is centred closer to the south-western J1230.6+3247 component with the fainter K-band ID at RA=12:30:37.96, J1230.6+3247 DE=+32:47:18.2 (referred to as J1230.6+3247A), and we consider J1230.6+3247 this to be the most likely near-infrared counterpart. J1231.2+2538 This is a compact radio structure with a faint K-band ID at its J1231.2+2538 centre. J1231.3+3724 This is a compact radio source with a faint K-band ID at its centre J1231.5+3236 This source has a very extended radio morphology with a K-band ID J1231.5+3236 at its centre. There also seems to be an overdensity of radio J1231.5+3236 sources close to the radio source, possibly indicative of a J1231.5+3236 cluster. J1232.2+2814 This is another compact radio source with a faint K-band ID at its J1232.2+2814 centre. J1232.6+3157 This is a small but extended radio morphology with two bright J1232.6+3157 K-band counterparts towards each of the extended components. This J1232.6+3157 could be a superposition of two sources or one radio source with J1232.6+3157 two plausible IDs, or alternatively it could be lensed. J1232.6+3157 Spectroscopy will be needed to distinguish between these J1232.6+3157 possibilities. The K-band magnitudes of both the northern object J1232.6+3157 (J1232.6+3157N) and southern object (J1232.6+3157S) are given in J1232.6+3157 Tables 2 and 3. Given the similarity in K-band magnitude, the J1232.6+3157 distribution in K-band magnitude of this sample is not affected J1232.6+3157 significantly by choosing one counterpart over the other for J1232.6+3157 this radio source. J1234.3+2605 This is a double-lobed radio source with a plausible K-band ID J1234.3+2605 towards the eastern lobe. There is also a fainter K-band source J1234.3+2605 at the centre of the eastern lobe at RA=12:34:24.12, J1234.3+2605 DE=26:05:51.4. Both are within 1.5-arcsec of the centre of the J1234.3+2605 radio lobe and either could be the ID. We assume for this paper J1234.3+2605 that the brighter source is the ID, as it lies along the radio J1234.3+2605 axis. J1238.2+2613 This is a compact radio source with a K-band ID at its centre. J1238.8+3559 This is a double-lobed radio source with a bright K-band source at J1238.8+3559 the centre of the radio structure, which we take to be the ID. J1238.8+3559 There are also two further K-band sources stretching along the J1238.8+3559 western lobe, which could be due to jet-induced star formation, J1238.8+3559 although spectroscopy will be needed to confirm that these J1238.8+3559 objects are at the same redshift as the radio source. J1243.7+2830 This is a compact radio structure with a K-band ID at its centre. J1243.7+2830 There is also another K-band source of similar magnitude that may J1243.7+2830 be interacting with this central galaxy 1.3-arcsec to the J1243.7+2830 north-east. J1245.9+3320 This is a slightly extended radio source with a faint K-band ID J1245.9+3320 at its centre. J1246.4+2516 This is a compact radio source with a faint K-band ID in the centre J1248.2+2747 This source has a slightly extended radio morphology with a fairly J1248.2+2747 bright K-band ID close to (~1-arcsec away from) the centre. J1249.0+3615 This is an extended radio source with a bright K-band ID at the J1249.0+3615 centre of the brightest point in the radio emission, which we J1249.0+3615 take to be the core. This galaxy has a very close possible J1249.0+3615 companion ~1-arcsec to the north with which it may be interacting. J1249.0+3615 The 74MHz centroid for this source is ~12arcsec to the north of J1249.0+3615 the core position quoted here. This may be because the 74-MHz J1249.0+3615 emission arises from a more extended, optically thin lobe. J1249.7+3408 This is a compact radio source with a very faint K-band ID at the J1249.7+3408 centre. There are also three fainter sources in the immediate J1249.7+3408 vicinity (<6-arcsec away) of the ID, which may be associated with J1249.7+3408 an overdensity of galaxies at high redshift (the K-band magnitude J1249.7+3408 of this source means that it is likely to be at z>4). J1250.4+2941 This source is a highly extended double-lobed radio source in the J1250.4+2941 eastwest direction. There is a bright ID at the centre of the J1250.4+2941 source, with a line of three fainter sources aligned along the J1250.4+2941 western lobe. This is highly unlikely to be a chance alignment, J1250.4+2941 and therefore these three sources may be due to gas compression J1250.4+2941 by the jet causing increased star formation, or could be due to J1250.4+2941 a preferred orientation of galaxy overdensities with respect to J1250.4+2941 the jet axis. Spectroscopy will be needed to confirm whether J1250.4+2941 these are actually at the same redshift as the radio source. J1252.7+2207 This is a fairly compact source with a K-band ID near its centre. J1252.7+2207 The astrometry on this image is only good to ~1.5-arcsec; J1252.7+2207 therefore it is very plausible that the ID is actually at the J1252.7+2207 centre of the radio centroid. J1253.4+2703 This source has a very unusual morphology in the radio, and in J1253.4+2703 Cohen et al. (2004, Cat. ) we suggested that it J1253.4+2703 could be a cluster relic. There is a bright K-band source near J1253.4+2703 the centre of the radio emission, but spectroscopy will be needed J1253.4+2703 to confirm whether this is associated with the radio emission. J1253.6+2509 This is a double-lobed radio source with a K-band ID centred on J1253.6+2509 the northernmost extent of the southern lobe, along the axis of J1253.6+2509 the radio emission. J1256.9+2811 This is a compact source with a very faint K-band ID consistent J1256.9+2811 with being at its centre.