We were glad to find a spot last night in the rain where we could get the boat in to the side.  A further benefit was that it was firmly aground at the bow so even speeding boats hardly moved us.  It did take a bit of work to get back afloat in the morning though.

Fortunately the heavy rain forecast for the day stayed to the north of us, and we had just a couple of blustery showers on the way back from turning below Somerton Deep Lock.  A word of warning though - the winding point  marked in our aged Nicholson's guide would probably be no use to boats longer then 60 feet.  It is also very narrow, and not all that obvious on approach.  There seems to be a better one, though not marked in the guide, above Somerton Deep.  

Edited to add: I've just checked in the Waterscape Boater's Guide, and the only winding point marked is for 60' above the lock.