Not unusual I would agree with Cobber & on the supplier recommendation, I have had parts from MG Mania, however there’s another company whose name is one letter different which I could very comfortably live without. Do check their pricing, buying direct might prove more advantageous than via eBay. At the end of the day it’s the carriage that will prove the clincher.
I’ve no doubt you would want get on with the job, but I’ve an original SU plastic example (why?) & one or two later aluminium units, one of which came off a Freelander, if either of those were a 52mm body you could have that for the carriage & that would be with a TPS.
The fly in the ointment is I’m away for at least another week providing we’re not washed out into the North Sea, then I’ll have to locate them etc.
M