I used to own a valeting company moons ago but still kept back a machine polisher and keep stock of cutting compounds etc as I do invariably machine polish the odd car by word of mouth. I usually charge £100 a day and a car with fairly rough paint will usually take up the majority of a days labour so I charge upwards of £80. If you have a go yourself then just be sure to keep the polisher's speed down and keep the area your working on well wetted (water in spray bottle is easiest). It's not that difficult but after years of practice it is such a simple yet still time consuming task. If it's just light swirls on the paintwork then as stated above a straight forward cutting compound followed by a finishing compound and then a hand polish to finish will have you looking like new again. People are so surprised when their car is finished as it really does come up like factory fresh if you do it right. Beware of edges like wing tops, wing mirrors etc that have sharper lines as the paint there will burn through a lot easier than on a flat panel, it also polishes a lot quicker so you can whip over these areas quite quickly. If it particular dull / scratched paint then flatting down with a wet & dry grit is what is required prior to mopping, this can be beyond a diy job as it takes a fair degree of polishing out and knowing how far to go with the grit, always avoid wing tops with wet & dry as it'll quickly go through to primer. You'll need a jet wash handy as the cutting compound will make a mess and once dry will take some effort to remove, I usually blast excess off as I go along especially in the summer.
You'll likely be ok with a basic orbital polisher as it doesn't have the speed or power of a bigger MOP such as a Sealey etc.
Failing that, If your down Devon way at any time I can go over the car for you
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