Thanks! I've been to see a physio and it's definitely something deep in the Soleus and is acute rather than overtraining (I'd done several 50+m weeks previously with no problems). He did some manipulation on it (across the muscle) and then used laser and a heat machine - then gave me some stretches. I've got 5 more sessions and will rst ot for a further fortnight (which will be c4.5 weeks) before trying again.