For what its worth I have a very similar Humber Clipper Grand Prix from 1963
that I got for my birthday. Same color but with a black headtube, same 49-46
crank, Campy Grand Sport ders, Brooks Swallow saddle, and GB 66 brakes, and GB
bars and stem. It cost $120. I can remember borrowing my father's whitewall
cleaner and ruining the decals. Steve