Assistance with identifying this frame

[rhyslbw]

I'm just seeking any info on the frame prior to stripping the paint and matching a crankset, stem, and bars to the Campagnolo Record/Mavic wheelset, (and shortening the chain). Pretty new to the world of track bikes, but have been riding a track fork-end fixed gear for over a year and really like the improved response of this compared to the 1950s steel road frame with 27" wheels.

As far as I can see, the number on the bottom bracket shell is 5060, 5260, or 5760.

Any help would be greatly appreciated.