Not sure about proclean never used them personally, seen a few examples of their work, 2live and Dannyt, and they have done a good job on both of thier wheels.
Im going with Alloy Wheel Refurbishment in Bury as its closer to me and they give a 12month guarantee on the wheels they do.
Mine are going in to be refurbished on Saturday, when I get them back I will post before and after pics, well if they do a good job I will, if not I will hang my head in shame and never speak of this matter again.
Bury place charges 35 per wheel not painted, mine are costing 40-45 a wheel because they have to be painted Gold.