Firstly, a diagnosis of plantar fascitis but after several weeks and a bit of internet reading I wasn't convinced this was actually what it was.  Also, my physio had sent me to see a podiatrist who told me I needed orthotics.  I wasn't totally convinced by this and at this point decided it was time to get a second opinion. 

I went to see Gary at Pro Physio in Chester and he said firstly we need to try and eliminate a few things, so the first test was to eliminate it being a stress fracture.  He put the ultrasound over the heel area of my foot and gradually cranked it up.  It its a stress fracture as the ultra sound frequency goes up I would likely feel a referred pain as it vibrates through the crack in the bone.  Lo and behold this is exactly what happened.  So its 99% likely I have a stress fracture.  Although not great news it could be worse and at least here I know its 6-8 weeks of no running and hopefully not much more.