If college Road car park is full there's a little side street opposite the church where you can park, it's pay and display again
Trying to navigate internally through the hospital is crazy. I worked in patient transport before going on maternity so had to find many departments. If college Road isn't any good you could always park at the Lido and walk through St Paul's, through the cafe and follow the corridor all the way to the end where the lifts are on the left. Then you need to go 2 levels up in the lift
There is free parking for up to 4 hours beside the park along college road. About 5 mins walk from the hospital.
Hiya, for radiology 2 your best bet is college Road car park. That way it's just through the door and up 1 level in the lift. Otherwise you'll have to walk all the way around from the other car parks