SK53
Two sources : a) OS OpenRoads data (big download); and b) Open Data search on OSM-Nottingham (http://osm-nottingham.org.uk/?z=16&lon=-4.50657&lat=55.61978&bgl=OSM,1,15&s=kilmarnock&st=SearchOpendataJson&uc=1). Latter has a couple of entries which may help confirm or better.