@mjdronfield:

Correct: In fact to use the onboard dispenser, you need to turn down the nozzle pressure, it will not draw from the tank at high pressure with most pressure washers. Snow Foam dispenser is the way to go, as I already said Traffic Film Remover (TFR) goes in the onboard tank for the prewash. The snow foam produces a nice sudsy lather for your main wash using microfibre mitts, those 2 products are really all you need, if you buy the right ones.  “If it ain’t broke, don’t fix it” -where’s the fun in that?

So, tried the foam a few weeks back. Didn’t go so well. The bottle said 5:1 ratio, so that’s what I put in the bottle. Not much foam, didn’t really stay on the car…. I’d obviously not allowed for the water from the pressure washer further diluting it.

Planning to try a 50:50 mix in the bottle next time.

What mix are you chaps putting in the bottles?

 2011 Range Rover Vogue SE 4.4 TDV8

Previous cars :
2003 Range Rover Vogue TD6
1999 Discovery Td5 ES
1995 BMW M5 3.8 6 speed
1992 Range Rover 3.9 Efi Vogue
1992 BMW M5 3.8
1988 BMW 735i SE
1989 Ford Sierra XR4x4 2.9i
1981 Ford Fiesta Supersport

I probably use about a 1:5 ratio in the bottle, I have the setting on the bottle to 3 for thick and it produces a quite thick foam that sticks and slowly drips down over 5-10 mins. I don’t have to dial the pressure down on the washer. MY23 PHEV HSE
MY19 Disco 5 HSE - gone
My16 Disco 4 HSE LUXURY - gone
My12 Disco 4 HSE - gone
MY05 Disco 3 S - gone but not forgotten