If you join the Royal Engineers (a semi-logical place for a civil engineer) then you can stream into the PQE (Professionally Qualified Engineer) world. There's plenty of propaganda about this option at the various RE websites but in broad terms:
1. You get to command as normal, and then command a Specialist Team.
2. You get two bites of the promotion cherry to Lt Col (albeit probably slower than mainsteam).
3. you get to spend 18 months at Chatham/on a civi attachment which will allow you to sit the Chartered Engineer exam
4. You probably won't get to be a staff officer outside of the stream, although a few do.
I'm not a "Pointy Head" but I've worked with them a lot, mainly on operations where they spend all their time (not many of them, plenty of operations!) and they're useful blokes to have around, albeit some of them are utter, utter noshers (mainly the older versions).
thanks, seems you can develop in a similar way to the comerical world. My main concern is that i wouldn't be an ordinary officer and just shoved in an office somewhere doing a civilian job in army clothes.