A mist coat is when you spray the body, but it doesn't cover the body with paint, it only lightly "mists" it. The idea is that the light coat of paint adheres to the body better than a heavier coat, and also acts as a "tooth" for the wet coats to grip onto to help avoid runs.
To strip the paint off, we have a product here in the states called Castrol Super Clean (I believe it's purple). Just fill a tub with a bottle of the stuff, submerge your body overnight and rinse completely. The CSC will take off paint and primer to the bare plastic, and the most you'll have to do is scrub it lightly if anything is still sticking. Remember that you should wear gloves when you do this. Also, you can strain out what came off the body and reuse the CSC. You can also use it to strip the plated "chrome" from body parts and wheels as well.