I use Williams waterless car cleaning/polish bought off Ideal World. £20 for 4x 1 litre sprays which should do 6 medium size cars.. Has Canuaba wax in it. Protect paintwork from vandal spray paint - use some Williams locally and it dissolves the spray paint BUT you must have Williams on before the vandal spray. Same with road tar - use Williams locally and it dissolves the tar. Use with microfibre cloths to apply and another for polish. Last summer I then started to use Carplan Number 1 on top of Williams. Car stays cleaner longer, then needs less cleaning effort. £8 from Wilko (and other places), one spray bottle will do 4 medium cars, so very cost effective - both Number 1 and Williams.
I don't like using the standard type wax polish, takes too long, and in the summer it dries hard and difficult to remove. Williams can be applied sunny weather and damp weather.