Update, first commute in this morning. Short due to various reasons but still got to test all the bits and everything is running nice and smooth. Looking forward to having the small ring available for climbing Maze Hill this evening, it's been a while.
On Saturday I fitted (help fit, drank tea and watched a mate fit, delete as you feel fit :-) ) - 9 spd KMC chain, 10 speed 105 chain rings, 105 front mech, Tiagra 9 spd rear cassette (11-30, straight replacement) and a pair of very funky hand built wheels from our own
@Spoked Wheels . We had a little problem setting up the front mech (I don't know if it was a flat bar shifters vs drop shifters thing, but it adjusted out with a bit of fiddling) and aside from that everything was good.
The bike runs nicely, the wheels suit the look of the bike, which was nice to see as I'd gone completely away from the all black look of the originals. Very happy with it all and looking forward to many miles of commuting before the next set of mucking about (unless the germ of the idea of replacing the bottom bracket with a hollowtech one takes in which case I could end up changing things again earlier rather than later :-) )
Again, thanks for all of the advice, really helped me out.