Im fairly certain there was a 25 and 27 as well. If I had to guess, I'd say there was some Diana involvement with the tooling and parts for the Bremas. The very close facsimile, especially the sight ramp and could another European makers get away with making copies?
I have no plans to buy one as I'd always go for the real thing first. I find it difficult to buy any air rifle without it having Diana/ Original/ RWS etc stamped on it but if a Brema came up at a sensible price, I'd maybe consider it.