Hi and welcome to the forum. About the speedometer, is ”vintage ” a brand name or is it just referring to a type that is suitable for the car?Is it mechanical with a cable connecting it to the transmission or electrical connected to the sender on the trans by wires only?
See the link page to the left in the aqua block at the bottom for MG Magic and Moss Motors for parts.
I think the brand is vintage as I believe that is what I have. If the speedo is broken perhaps you want to take it out and send it to a speedo repair facility. These may be difficult to locate now as they are pretty old.
It is a brand name they were made by a company who makes boat gauges for CMC I looked them up once, the name escapes me at the moment. They may still be available at MG magic. I spoke with Brad about them and he is the one who told me the story about the boat manufacturer.