So I have just got back from the physio. It turns out that one of the ligaments in my left ankle is no longer working. Or it might not be there. Or I might have damaged it. They aren't sure. However, apparently standing on one leg is the way forward. So I'll be doing a lot more of that over the coming weeks.
One thing that has come out of all this is that I've been told to avoid the exact movement that releases my left foot from my clipless pedal. They won't say that it was the pedal that did it , but I might "wish to consider other types of foot retention"
I should apparently not be running still. Or rather I should not be running. At all.
I'm currently researching platform pedals and straps. I never really got on with clips and straps.