Had the operation yesterday. Not quite as bad as I thought it would be. They did the operation by local anesthetic, can't remember what they called it, Lumber something, they paralyse you from the belly button down, then insert a camera and things and remove the stones. The operation was a little painful, but less than I expected, the worst bit was having to lay still on your back for 8 hours afterwards.
Feeling a bit better now, and looks like will be able to go home home later today.
Below some pics of my hospital room: