What actually works?

[Sorka]

I can't exercise properly (dodgy body and physio will only let me join a rehab gym where you can only use the cardio equipment for max 5 mins at a time) ...

You'd be surprised what 5 mins of cardio can achieve. I have had three different weight program's done for me and each have had only two lots of 5 minutes of cardio (x-trainer, bike or treadmill) amongst other weight and Pilates based exercises. So there isn't all that much huff and puff but you still get some results