I have seen where several people have found a "generic" three point harness with retractors that seem to work well. I bought a set from Richard at Banks back when I was building my care (almost 20 years ago, now) but I couldn't see how they would work. Maybe I missed something and it was probably something obvious. I no longer have them but Richard sells seat belt sets for a bit over 50 pounds. I would think that they would work - at least he could explain how to make them work if there was a trick to it.
In the end I used my original belts sending them to an operation named Ssnake-Oyl (
http://www.ssnake-oyl.com/). They did a great job re-webbing them in the color of my interior but they could not rebuild my retractors. Luckily, they were in pretty good working order. I mention them in case you get an old original set. They have some generic belts that might work but I wouldn't expect them to know about Europas.