I believe the rear drums and drive shafts came from a Hillman Imp, a very small rear engined car, 875cc, made in the 60s. The hinges for the engine cover on a Europa come from the front bonnet (hood) of the same car.
My car has 3 keys not splines, and the hub was very tight on the shaft due to rust. Emery paper soon made the hub a slide fit again, soon to be re-assembled with Loctite bearing stuff when the hubs come back from Banks at 108PCD.
I might put my name and address on the rear wheels, just in case they part company from the car.