If you can get the steel parts that are broken it's very straightforward to do these yourself.
Cleaning the chassis, I would recommend using "Naval Jelly" and a stiff brush... possibly more than one time. I am having great results with that - it's for cleaning steel, removes bluing and rust. Repairing is as simple as desoldering the parts, making sure they're clean, then putting it all back together.
I have repaired a couple of eurosports previously, and had to do some creative replacement of the shaker keepers - not even sure if they call them that anymore. But mine are all for play and not raced. If you are really in need, I can do the work for you, but I am not a pro. this is a hobby. I just take pride in doing the refurbishments. (I did a lot during this pandemic).