Okay, so I did change a few things and have received my final frame drawing that I have now approved. I opted to go for a T47 BB in the end. BB30 wasn't such a great idea in hindsight and I think T47 will give me lots of felxibility in the future as to what cranks I can run.
I also asked for a longer ISP, now 740mm instead of 700mm - too short is a big problem, too long, not so much!
I also had fixings added to the seat-stay and chainstay bridges for mounting full mudguards. Although this is very much going to be a hardtail for most of the time, having options for a rack and mudguards is just sensible. I also had additional rivnuts added to the seat tube so a second bottle can be used on the bike.
Final drawing attached