Yes, it’s true and thanks to TR for the tip, although Greenslade’s journey from Maoism to anti-Scargillism, to Provo fellow traveller does seem as if it could have been plucked from a Monty Python script. It seems that when Greenslade was a callow youth, well sort of, he was a member of the Communist Party of Great Britain (Marxist-Leninist), a Maoist breakaway from the pro-Soviet British Communist Party.
Here is the relevant part of a history of the CPGB (ML) taken from high-tide.pdf (High Tide: Reg’s Working Class Party)
The CPB (ML) reflected its leader with similar strengths and weaknesses: basically militant trade unionist, anti‐intellectual in temperament and regardless of it professed allegiance to Marxism‐Leninism, almost non‐ideological, operating with a set of beliefs instead of theoretical analyses and political correction in the light of practice. The theoretical poverty of the organisation was ‘well developed’ in what was the largest Maoist organisation in Britain. However the Party was not without its share of intellectual talent whose names entered the public arena: ‘Bill’ William Franklin Ash, the writer, married to Ranjana Sidhanta Ash, freelance lecturer and writer of South Asian literatures, Roy Greenslade , an experienced tabloid news sub before going to Sussex University in 1974, and its share of teachers, Dorothy Birch and lecturers, Fawi Ibrahim at Willesden College of Technology, and the former LSE lecturer Nick Bateson.
Interestingly, given the arc of Greenslade’s subsquent political journey, he was still in the Maoist group at the time of Bloody Sunday in Derry, the point at which, he says, his sympathy for the republican cause was born. When he finally broke with the party, and joined Robert Maxwell in trashing Arthur Scargill and the miners’ strike, remains an unanswered question. But seemingly his sympathy for the Provos survived.