Only 1 choice to my mind:
Brite Max Clean Max PH Balanced Shampoo
Review here: Scored 99% on detailing world :
Britemax Clean Max pH Balanced Car Shampoo 1G Super Concentrated - Detailing World
It's fantastic. £30 a bottle but a bottle last ages. Costs about 50p a wash from memory.
Thing about this stuff though is you wouldn't believe the shine. You wash the car and it looks as if you've polished it.
Here's one they washed with Britemax Clean Max on Detailing World:
Obviously with those reflections, that's a well polished to start with but even so.
With my car though, which has never been polished since I bought it as I've been getting all the problems sorted 1st, it still gets an unbelievable polished look shine. Even the neighbour came around and asked what I was using!
Water sheets from it and dirt can't stick as well so the car stays cleaner for longer.
I wouldn't use anything else!