Thanks for the very constructive comments. This is the third time I shoot a model, plus I've done family/friend portraits in the same studio.
I agree I have to experiment more with the lighting. They have 3 flashguns (2x250w, 1x500w). The problem with these sessions is they're set up for club members to have a go so they just place a softbox on either side, the one on the left at 1/4 power, and each photographer has a go at telling the model what to do, etc. Sadly nothing is learnt on the lighting side of things.
I can rent the studio for £10 any time though and have a proper play (which I have done twice with some family and friends) but I suppose the best way would be to read up first and try several setups.