Page's article is about as accurate as his soft, strong and thoroughly absorbent tome, Lions, Donkeys etc.
Mace, like Sharman, trained as a private individual.
The only UK Govt sponsored astronaut candidates were Sqn Ldr Nigel Wood (a tp and former Lighning mate), and an RN cdr who were selected ahead of an Army (RSigs iirc) lt col and MoD civilian candidate to fly on the shuttle in the late 80s. The missions were to have been in support of the Skynet programme. Sadly, although they commenced training, the Challenger disaster put paid to any hopes for a UK military space presence.
It is such a shame that Page's partial and inevitably inaccurate outbursts are given any column space.
Regards,
MM