I wrote on the old forum about my experience with plantar facsiitis. It is a painful experience and although you can run through the pain you worry about the risk of it becoming worse so as to need surgery.

I went to see a physiotherapist in Crewe, Mick Gill who fixed the problem in one session. The bad news is that Mick is dead now.

If your physio can't sort it out I'd shop around for another one.