Fudgey - Bodywork has to be clean, dust and dirt free. I use Isopropyl (panel wipe) before applying. Always best to do indoors, although i did do one panel outside and it was fine!
Darren - Very durable, it will last for years and doesnt wreck the paint at all if removed correctly.
I've completed the rear now, just bonnet and bumper to do, want to redo the rear quarter and one part of the tailgate, then she's finished!!