Well, it's not a 'particularly good' job but it is acceptable. Nobody is ever going to wash my car as well as I would wash it myself, but I don't have anywhere to wash it.
The place I go to is here:
http://goo.gl/maps/KgUEe
It happens to be ridiculously local in that it's less than 500m from the entrance to my car park, but I've seen all sorts of nice cars in there, and taxis and minicabs use them regularly.
My friend says these guys do a 'particularly good' job:
http://goo.gl/maps/Oqgd4
But bear in mind that he uses bits of cardboard he finds on the street to wipe off bird poo from his car and then wonders why it got scratched, whereas I know what swirl marks are and why you'd want to clay or machine polish it.
Neither of these guys are going to clay or machine polish your car for the £10 they charge (in and out).