According to findmystreet, USRN 22208301 (Decapod St) has a way running east to west, parallel to, and north of USRN 22207924 (Thornham Grove).  On the ground, that would mean the footway running alongside nos. 12-2 is part of Decapod St; and the roadway is part of Thornham Grove.   Your photo appears to contradict that.  On the OSM Map at present, the USRN refs seem to match findmystreet, but the names do not - too much Decapod St.   Will look for more streetsigns next time I'm there.