Just been to the Asda in Slough and found loads of car shampoo's there for £1 were £4 or £5 before I think! Bargain price as they do up to 300 washes. I am not sure if its online but most certainly instore!
Will upload an actual pic shortly along with proof (ie receipt) to confirm its valid. Not sure if its nationwide though.
Hope someone else manages to bag a bargain!
(I did check the HUKD site for the last month and could not find another posting for this)