Ok I checked the crank pulley and the spare tyre winch. The actual slot on each side is cut fairly deep.
From the bottom of the notch to the bottom of the centre hole is only 8.5mm, but you could have the hole for the cross pin up to 25mm up the shaft and it would still engage.
Something to consider is that if you have the pin too far back and find it slips out of the slot, you can just trim a bit off the end of the shaft.
I don't have access to an original Inter crank handle to see where they had the pin, but hopefully one of the other members here may have one and post up a pic of the end of theirs.
They must have been very useful for something other than starting our Inters and raising/lowering the spare wheels, as a lot of us are missing them.
Either that, or there are a lot of them slowly rusting away in the bush where they were forgotten and left after changing a flat tyre.

Greg.