Does anyone happen to have a height adjustment key to fit an
Orchestrelle (or similar) push-up player that can be spared?  With
round shaft diameter 8 mm (5/16"), at least 2" long, with T-bar or
similar at one end and square peg at the other measuring 3/16"
square and 5/16" deep.

Thanks, and keep on pedalling!

Jim Spriggs
York, UK