Thanks for the help guys.

The car was cold when I started washing it, the spots are all over the car, not sure about paint protection. Could be water marks as I was a bit tardy wiping it down at the end, but I don't think so as it looks like a residue of some sort. I'll have a go this weekend again. Not sure about which Meguiars product I used, green fluid, I'll check tonight.
Jimmy S, PM sent.