Nowp, defo wasn't the White Cliffs' disc.
One of my regular suppliers had an interesting stash a few months ago...mainly big ticket Deep sides, which included Tommy's River City (and White Cliffs discs), along with some others. I seem to recall another sparse looking label, maybe yellow in colour, that looked interesting, but failed to be Northern either side (not saying that's a problem!)...so I left it.
Went back and visited the bloke again yesterday...the River City 45 was still there, but the 'other' disc had gone.
Hmmm.