Mysterious fork crown

[TeamEndurame]

Can anyone identify this fork crown? Trying to identify what I've bought. The bike has been hand painted so has limited identifying mark on it. It does have Campagnolo 1010 dropouts and Prugnat long point lugs. It also has above bottom bracket cable guides. The rear brack cable guidesare on top of the top tubeThe existing seatpin, an SR dated as October 77 (G-77) is sized 27.0mm.
The rear forks are 126mm. The only other datable compotents on it are what looks like a Campagnolio Nouvo Record 2nd Generation front derailleur and a pair of Campagnolo 126mm hubs. The rest of the components fitted seem to be more 80s and 90s vintaged and added later (Shimano 1055 brakeset, Shimano Exage 300ex chainset, Shimano 1055 downtube shifters and a Shimano Tourney rear derailleur with a Shimano HG-20 6-speed. The headset is a 1" Stronglight a9. Some nive looking Ambrosio Prisma Elite rims. The weight of the frame would suggest something akin to Reynolds 531. I've taken the bottom bracket back to bare metal and there is no trace of a serial number. I've not removed the fork as yet to check for the serial number.
Returning to the fork crown, I've looked through pages and pages of pictures and can find no match. Any ideas?

 

[Midlife]

Looks very Vagner (ish). Back in the 70's it was trendy to modify lugs and fork crowns with files and drills. Might not look like a stock item after such treatment

 

[Midlife]

Any other pics of the frame? I wonder if it's been converted to Allen key brakes?

 

[torqueless]

Crown looks like a Milremo Giro that's had a bit of file work done on it. Common crown from mid '60s-mid '70s.

 

[TeamEndurame]

 

[TeamEndurame]

More pictures

 

[torqueless]

If it has 1010 dropouts, domed stay ends, Prugnat points and takes a 27mm pin it's almost certain to be 531db. That seat cluster is screaming: "Brian Rourke"... to me, anyway..

 

[Fifthgrace]

Rourke's usually have a wraparound seat stay, this one doesn't (exception being the R753 frames Rourke's made for Moducel Pro Team that were badged and passed off as Holdsworth in their last year of racing).

 

[torqueless]

Yeah you're right about the wrapover. OP could do worse though than contacting Rourke and asking if it's one of theirs, and if they reply in the negative, asking them who they think might've built it? That 'fastback/wraparound' can't be that common- probably the OP's best bet for identifying the builder.