Thanks smilesbetter , we were hoping he'd be fully sorted by now - in fact I think his knee is, just the foot issue now.
lotsofcats you asked how far we walk him. We took him for a walk today with the G-Paws GPS recorder attached to the lead. We did around two-thirds of a mile, the longest we've done so far. We managed to persuade him to go on past the normal route back home & do the full circuit. His leg seemed a bit tired as we reached home but he soon recovered.
Here's a Google Earth image of his walk. We started off down our close then left into the little park like area, back up the road alongside the country park, past the close that links back to ours then circled back down the next linked closes. Of course we were also with Lexie & Osiris