thanks to everyone for their input - i took it back to the body shop, it was what most people said, water getting under the plastic sheeting had damaged the paintwork
30 minutes later it was back to its old self!
in fairness, thanks to the guys at G and D Smart Repairs Bristol, did it straight away, no questions asked!
seeing these machine polishers go has made me think i need to get myself 1 and sort out the whole car!