For the OP - To get the best from the paint at minimum you will need a dual action polisher like the buff daddy, das6 or g220. Its all down to pad and polish combinations plus user quality as to how far and how good a job you do. As already said, its all in the prep. Take it steady and enjoy the process, dont rush. Expect to be a good day minimum to get moderate results, to get the best results you will easily be looking at 10-14 hours as DA's are far slower and less abrupt than that of a rotary polisher. As for the halfords polisher - Forget it. You will get just as good results by hand. If you do use it, dont use wool as this marrs paint and will need refining back.
ZermattV - The buff daddy is a very capable machine. Used in conjuncyion with lime prime on a 3M yellow pad will give excellent results.