I've finally started work on my Merlin road frame (Bob Jackson product, all 531) and have started in with 3M stripper and putty knife. I've found a rattle-can that's a "good enough" match to the original purple metallic, so it will be returned to more-or-less original appearance.
My question is regarding the brazed-on bit off the rear cluster: it's obviously for some center-pull brake QR, but which one? (Bike came with sidepulls so this braze-on was not in use when I acquired it)
here's a pic: