Having a nightmare with what should be a relatively simple job. First had problems with two bolts which didn't want to co-operate with being removed, past that things started to go to plan until it came to the last job of retract the piston. Some guides says it goes clockwise, some anti-clockwise dependant on when the vehicle was manufactured. Well to start with the piston didn't want to move, while I nipped into the garage for some tools my house mate in his infinite wisdom hit the brake pedal to try and release the piston but actually managed to pop it out and past the dust seal.

Now I can't get the piston to thread properly back into the caliper. Any ideas or help welcome before I take a match to the car.

ah man, he has done a number on it!

I would start by ensuring thorough lubrication, give it a drowning repeatedly of WD40 / Sillicone just to try break free any rust. Then you will need the windback tools to get it back in.in the meantime, take a pair of long needle nose pliers, spread it and try rotate it back into place.