OK so I know nothing about the transmission in the car apart from that its a 4 speed manual and may or may not be original to the car.
It has an issue with jumping out of 2nd gear when you let off the accelerator. For this reason I have sourced a cheap second hand unit which I'm hoping will tide us over until we can get the original rebuilt by a pro.
I will try to post pictures and the transmission number as soon as I get them.