I lean towards the idea that this was filed by the fake Ramekel. It's fitting the pattern of "invest in my business". I can imagine RB and Marion going to Luxemburg to file the patent together giving credibility to his business venture. The patent filing date is a perfect match with their European travel records:
17-06-1997 Mr B, according to international movement records – travelled to Japan with his outgoing passenger card saying he intended to spend 30 days in Belgium. (this is probably where MB got the Japanese stationery from)
23-06-1997- MB left Australia from Brisbane airport with two suitcases
25-07-1997 Fernand Remakel files patent for vacuum tube
31-07-1997 RB returned to Australia using name of “Richard Lloyd Westbury” on his passport following change by Deedpoll.
There are 3 other patents files by Ramekel. They seem amateurish and eclectic and seem to be registered by shell companies. One of the shell companies is using the address of a primary school. Each of these patents might be linked to other victims if they were filed by the fake Ramekel. Which is more likely (1) the real Ramekel files his first patent in the month that MB and RB are in town or (2) RB, with a known history of proposing business ventures to extract money from his marks, files the patent under the alias he was probably using with MB in the location he was probably travelling to with MB.