It's been a couple of years since I had to go there but I do remember towards the end, parking got a lot better. Around the time they brought in the disc system to stop selfish people using it for other purposes. Highly visible wardens IIRC. Sounds like it is still working.
First hospitals, now sports centres. Anyone you do want to be able to use their own car park? That is a very busy car park for a very busy leisure centre.