Not widespread but they do seem to be spreading slowly. Was surprised to see only six collections listed on Zootierliste for them (albeit not yet including Newquay, so at least seven now!). Feel like I've seen them quite a bit lately, but I think I just happen to have been to the right zoos for them!
They're exactly the sort of thing I'd expect to be popular with private keepers, so I suspect the zoo population is the tip of the kangaroo rat iceberg in Europe.