Thanks everyone, you've been most helpful. I am steering towards a back-inflated bc or a dragonfly type. I've only used hire jacket bc's to date and they have been ok but a bit rib-crushing when inflated. Unfortunately Tassie only has a few v. small dive shops, so bc's usually have to be ordered in (after paying a deposit) so makes trying and testing various models a bit tricky! But thanks, you've helped me narrow it down somewhat!