domsz4 said:
i used the A1 wash in liverpool a few times, you see some pretty fancy cars coming out of there (the local jag/landrover dealer goes there) and tbh never had any trouble and the car is usually super shiny after. the only thing i dont like is when they put on the screen as it smears really bad. if your in a bind and you really cant get to wash it i would say use these guys or the equvalent but chose well there is another one nearby that i wouldnt go to at all.
Unfortunately, if someone has a nice car doesn't necessarily mean they know how to clean it properly!
It's like anything in life - there are many way to do the same job! For me personally (and a lot of car owners) the mass market roadside car washes are a no go area....

I am sure there is a thread somewhere explaining the reasons why but one of them is the harsh chemical they use to clean your car. They can have a long term damage to your paint work, wheels etc...