This is a How Too article I posted to the Australian 2002 Facebook page giving the steps in the Right Hand Drive ATE boosters disassembly and repair. I found there is nothing on the internet with any real detail on rebuilding the RHD units. Hope this helps someone. I did have the benefit of a NOS genuine ATE booster rebuild kit which are no longer available however most seals are available separately via brake component companies and others.
BMW-2002-Brake-Booster-Rebuild-pdf(1).pdf