Picked this up on eBay very cheaply. Fully working, with 2 controllers and 2 cartridges. The RF video output it useless so I will add a composite video output at some point. I’ve had a quick look around the internet, and I cant find out much about this system. Rare? Doubt it….
I believe that Prinztronic is called Radiofin outside of the UK.
Here is one of the cartridges, and one of the controllers.