Can you help to identify these frames, bikes or parts?

My mates just bought a track frame off ebay. It's supposedly Reynolds 531, has undrilled fork and has "Made in England" stamped on the bottom bracket (with a faint sn we think is 6864).

Has nice lugs and a cutout BB.
Anyone got a clue what it is?

Thanks
Monsta

I was following that on ebay, wasn't dirt cheap from what I remember?

does look well made though.