Window regulator- 1930 Mulliner Box.

[Austinsixandahalf]

So now I can see the regulator, I can understand why it will wind down (gravity assisted!) but only partly up. Both the quadrant and the cog it meshes with are very worn. Comparing a spare ?Austin-Healey Sprite regulator quadrant (which I feel certain was common to many BMC vehicles), it is pretty much identical - and indeed could be used to replace the original item. However the original cog is of a different diameter so would not mesh. 
Would appreciate any advice here please. Don’t really want to go the way of a rubber wedge to hold things up!