I don't think anyone is disputing that. We have a Polish hand car wash near us that does an excellent job for about the same price.As I said at the outset.......the £15 valet is excellent value. I drop it off, go and do my shopping, have a lunch in town then pick it up on the way home. Can't complain with that.
But it isn't a Valet. It's a reasonably thorough clean.
As others have said, a proper Valet is expensive but the car comes out looking like new.