Ah Yeh, that's occasionally a problem. Same thing sometimes happens in enclosed spaces (hence I also have a 90 degree one).

You'd probably need a special screwdriver just for that use then. Unless anyone else has ideas, either buy one or go down to a hobby ship and ask to borrow it for a one off thing (individual screwdrivers shouldn't even cosy you a pound though).

Just find a little handyman shop or hobby ship and you should be able to get the individual item and be able to test it.