Thanks for your reply Karielle,

I went to see a physio today who says that I have neural tension, and has suggested that the pain is referred from the back. I have been experiencing a little discomfort in the right buttock along with the calf pain, but I wasn't sure if they were related.

He said that my slump test was positive and has given be some stretches as well as performing some "mobes!"
It is reassuring having seen the physio that I am going in the right direction now. He said that the original calf strain could have been a bit of a "red herring" or could have had a neural component.
I feel a little like I have wasted peoples time on this thread, and I just wanted to say thank you for all your help. Perhaps this will encourage people with a similar problem to consider ruling out neural causes with a physio.

I am aware that a buldging disc can cause these symptoms, (which I would like to think I don't have!). Presumably one can get "tightness" in the sciatic nerve without serious back pathology? I am still aiming to be good for Sept and the rugby season!
Thanks again for your help and patience,
Guy