I would phone the clinic you go to or the hospital which you are having your surgery at and ask them :). Think they say 24-48 hours beforehand but better to phone and make sure xx
Theres some roadworks so make sure you turn left just before the bridge and its the slip road up the hill to the left.
The car park is quite small but its a very small hospital! Just go through the main entrance, the staff are sooo lovely.