tashy - because I moved to Woodend and getting to the physio is pretty much an all-day round trip, my physio gave me a program I can do on a fitball using a special stretchy thing that you can tie round a door handle. Sounds stupid I know and I haven't tried it yet because my SPD has actually been very manageable but could you maybe ask your physio about that to save you some dollars? Happy to PM you my physio's details too if you like.