Bike Forums - Mystery bike, French, Shimano, English BB?

What on earth is this bike? Found near the south coast of the UK, its got an odd combination of bits, but also some aspects of quality. I originally posted the bare bones of some these details inconclusively in the C&V forum, but what follows here follows further investigation including looking inside the head tube for any remnants of a headbadge fixing (didn’t find anything), as well as the indicators from that earlier post.

What follows below is a list of everything that defines the bike. I’ve put pics up here (in its work in progress state):

http://s1261.photobucket.com/albums/ii594/empiricist1/

Even if you can’t make a completely positive id, some informed guesses might be useful!

Frame:
no headbadge or holes (checked inside head tube)
BB accepts English threaded cups
BB stamp underneath = “DD 136” or possibly “DD 196”
Butted tubing (seatpost = 27.2mm)
Campy rear dropouts (spacing =122mm)
See lugwork leaf detail on pics
Paint is either original or was from a bare metal respray
Seat tube measures more like 58cm than 23” – although the measurement is tricky because the top of the tube is scalloped
I’m told Reynolds decals are circa 1984 (but may not be original)

Components:
Tange headset, Shimano light action shifters + mechs, 105 cranks, Shimano BB Axle with adjustable cups, Shimano SLR brake levers. Biopace chainwheels.
Rigida wheels, Maillard hubs (6 spd helicomatic freewheel), Weinman 570 QR callipers.
Handlebars are Raleigh and a blue San Marco Rolls saddle was with the bike (but not fitted yet)

Any inspired guesses will be welcome!
Regards, Joe