Thanks Mark, you’ve clarified what I’ve sort of been thinking, that the numbers point to it being made by Heuer for Zodiac. Like you say though it doesn’t necessarily confirm this either.

Looking around the web a little more to see if I could find anything else on it, I did find a couple of old threads from here and a watch for sale in Germany.
http://chronocentric.com/forums/heuer/index.cgi?page=1;md=read;id=2332

http://www.watch.de/archive/archive_france/heuer-chronograph-vintage-42mm.html?___from_store=archive_germany#

http://www.chronocentric.com/forums/heuer/index.cgi?md=read;id=42387

The pic in the first thread is gone but the description sounds similar to what I have. The watch for sale in Germany marked Heuer. It has the same case/ref#, with a plain black dial, white sub dials and a Val 7734. The last link shows a similar watch to the one for sale in Germany, with the consensus being that it was/is a franken.

Eddie