As I was all-out of snow foam, I took a run into Halfords to see what they had, and bought some of this stuff.. was about a tenner for two litres, so expensive but that's Halfords for you..
Verdict - Foamed great (1 inch in foam lance bottle), smelled fantastic (like marzipan) and dwelled for around five minutes. Seemed to work better than the well-known pH neutral foam does at shifting dirt
However I'm not sure about it's wax-safe rating as the bottle did have an 'Irritant' warning, unlike the pH neutral snow foam (can't remember the brand)
So... not a bad, if expensive, product if you can't wait for internet delivery and need some foam in a hurry!