Be hard to find just a machine polish as people generally want to do the job properly.
Ideally, to machine polish you need to wash the car, decontaminate it to remove any tar or other fall out from the paintwork, clay the car to get the paint cleansed and clean and then can look at machine polishing it.
Its simply not a case of run around the car with a polisher after you washed it. Something as large as a A4 you could spend 3-4 hours prepping the car before its ready to polish.
I'll be doing mine soon, and plan to spend the whole day tomorrow prepping the car and going round all the minor details, then can get the car inside and polished with the polisher to remove the swirls.
There are a number of good glazes you can get that will mask some of the swirls, but thats only temporary. But if your selling the motor, something like that might be ideal for you.
Personally id pick up a clay bar kit off ebay for £12 (bilt-hammer or something else off a cleaning site) and go over the car with that. Then get a good hand polish and glaze on top followed by a wax to seal your work in. What it masks depends how bad your swirls are in the paint.