My tame mechanic does loads of cambelt changes on MGF/TF. I've sat and watched him do mine a couple of times. He makes undoing the crank bolt look trivially easy. Mind you, he does have the car up on a 2 poster. He basically pokes a big screwdriver through a hole somewhere underneath to jam the starter ring. With the other hand, he uses a 24" breaker bar to undo the crank bolt by applying his fairly considerable weight downwards from below (tree swinging style). It takes him seconds. He also has a handy 5ft high bottle jack to support the engine when he undoes the RHS engine mount. Beyond that, I haven't a clue what he's up to. I might have to learn, though, because he just retired