For what it's worth, I no longer sit for more than 10-15 mins unless driving and that seems to be the major factor that I was ignoring in the run up to this latest episode.
It is certainly on the mend as 3 weeks ago I couldn't walk at all, but won't be jogging again until at least the new year.
As for the traction it's quite gentle and cycled maybe 15mins at the most. I accept that it's now a weak spot and always will be so just have to exercise caution.