Go past Cambridge all the time in both microlights and spamcans. Always listen out so I know whats going on and then get a FI service if required. I dont know if it was flexwings or 3 axis guys that you saw but with flexwing they would definately have seen you as the viz is so good and would probably have been listening to Cambridge too.
I really wouldnt worry about their standard of airmanship as I am sure they would have been in their element whereas you were deprived of your sight out of the window which would make any VFR pilot jumpy. I am sure that we can all exist together if we fly constructively and understand everyone else.
I feel much happer in a jolly old flexwing cos we always see the GA guys before they see us!!!!!