Procrastination Rules!
I meant to get round to it - Honest!. Having put up with the LT77 take-up clunk on my 110, it's finally let go.
So - exchange gearbox needed plus the new cross-drilled input gear on the transfer box.
I've looked at Ashcroft's website for an exchange unit and they seem reasonable. (Didn't they used to offer a fitting service?)
Anyone got any better ideas? Horror stories?