My rear breaks keep locking up when stationary overnight and i have to rock the car back and forward to release them which can't be doing any good .

Any suggestions

Usually only happens when it's wet/salty or someone fits sintered pads but on the fabia you probably want to fit uprated return springs and strip/clean the pads. Costs next to nothing (copper slip/brake cleaner and a bit of time).

Thanks for that ,i will try that tomorrow.