Having looked at the brochure again, it seems that the "Master" was a BM900k but without the stereo light, although the decoder could still be fitted. It also says "Master" under the B&O logo not Beomaster. I wonder if any were made, it cant really have been that much cheaper to make than the full BM900k. I have sent Peter a scan of the brochure so hopefully it will be online soon.
Guy, I will email you scans of the Beo610/TR26 from the brochures in the next few days.
Richard