Bit of an update. So I was taking Naproxen twice daily for two weeks on the advice of the doctor, this started to reduce the pain I was feeling, but around the same time I bought a night splint which I started using. After a few days (nights) of using the night splint the pain had lessened a lot, with virtually none first thing in the morning. I went over to Slovakia for a few days holiday so risked a 6km trail run (in Salomon Speedcross 3 shoes) which went fine and didn't cause any extra pain during/after the run. So far so good.
I gave it another week after I finished the Naproxen, the pain came back a little but not much, so there's still some healing to do. I did a 5km road run a few days ago (Brooks Puredrift 4mm drop) and again, no pain during/after the run. The pain comes and goes in 'twinges', I can be driving the car or sitting at my desk and suddenly it'll be like a sharp burning pain in my foot - though not as bad as a month or two ago.
About a week ago I also bought a Compex Runner (EMS machine that also does TENS) as I read they can be used to relieve/heal tendonitis issues as well as for strength/recovery training*. I've been using this daily on my feet, and every other day on quads/hams/calves. It's a bit early to say if this is having much effect at the moment.
I went back to the doctors today and had the steroid shot in my left foot (not ultrasound guided - just done by someone who does lots of them). I was pretty worried about how painful it'd be but honestly it wasn't any worse than having an IV put in, I was pretty relieved! Maybe I have a high pain threshold or was just lucky she didn't hit anything too tender!
I've been advised not to run at all for 1 week, and then the doctor is happy for me to start doing a sensible amount of runs as I see fit, as long as it's not causing more pain then I'm good to go. If there's any pain left in 2 months (unlikely seeing how much it's healed lately, unless I overdo it again) then I can go back for another shot, this time guided by ultrasound.
The doctor gave me lots of good advice, and was impressed that I'd tried to make sure my running form was good rather than just buying corrective shoes. Some things she suggested, which I told her most of which I was doing already from advice on the net, are:
Rolling foot/arch on a frozen bottle of water.
Rolling foot/arch on a golf ball.
Gentle stretching once or twice daily.
Sleeping in a night splint.
Reducing the running until it's healed up.
Massage etc.
She didn't mention using a hard ball on the calves but I'll carry on with that, and I'll carry on using the Compex as well.
I'll update again in just over a week when I've done my first run.
* Some links I found about using a Compex for plantar faciitis.
http://bridgerridgerun.wordpress.co...-prevention-treatment-and-healing-techniques/
http://trimadnessblog.wordpress.com/category/plantar-fasciitis/