Mick,
Unless you have a completely different door to ours you definately donot have to remove door panels etc.
I watched the guy do ours and all he did was, having removed the door handles and the lock edge cover was to remove the 2 screws holding the lock into the metal door frame. He then withdrew the lock and reversed the procedure with the new lock.
10 mins max.
I gave our lock to someone else on the Jardines and he did his himself without any problems.