531 Frame - Compound Wishbone Seat Stay 1993/1994?

A few days ago in the darkest back corner of my shed I stumbled across an odd form ply jig with a large window in the centre and all manner of small timber spacers and guides fastened to its upper face. I wondered 'What was this used for?', upon turning it over a single word written in carpenters pencil was evident, simply 'wishbone'. That triggered it, it was a simple jig for the building of a compound wishbone seat stay arrangement. The wishbone was built using an orphan fork blade and two normal 531 double taper seat stays, a boss was machined for the brake and set into the the fork blade and the stays were cut and shaped for fillet brazing to the trimmed fork blade section. An elliptical reinforcement plate was made for the attachment point on the set tube. Now do I have a photo? Yes this is the frame built to utilise the compound wishbone seat stay. Built 1993/1994, I think?