[CR]WTB: Williams AB-77 BB & Rings

I'm trying to complete my ca. 1968 Geoffrey Butler and am in need of a BB and rings for my Williams AB-77 crankarms. The BB must be English treads and this is the one with the splined shaft ends. I'll consider any size rings but prefer 50/44 if anyone should have them. Does any other brand of ring have the same BCD? NOS is prefered but good used or better is definately ok and probably more realistic.

For those interested, pictures of the frameset can be seen in my wooljersey album:

http://www.wooljersey.com/gallery/Eric-Elmans-Bicycles

Thanks in advance for any help or leads,

Eric Elman
Somers, CT USA