My late grandad was ground crew on Lancs both on squadrons and at an MU (at Ternhill?).
I remember him telling me, it must be over 30-35 years ago now, about the cable cutters in the wing leading edges and about someone who was new to the Lanc losing fingers in one while working on the wing in the dark one night.
He said that after that they always showed the new lads how they worked by dropping a bit of old broom handle in the slot and chopping the end off of it!