True that Metcalfe and Mosley were married to sisters, but Mosley's going around the bend to fascism from respectable politics pretty much coincided with his taking up extramaritally with the equally fascist Diana Mitford Guinness, whom he subsequently married after Cimmie Curzon died. Lots of respectable people were associated with Mosley until the New Party days, after which they dropped him with haste. Metcalfe's connection to Mosley here is a bit too guilt-by-association for my tastes.

More relevant is Metcalfe's own wife, Alexandra, who was also having an affair with Mosley, which continued well into his Blackshirt days. She was tarred fascist in the press, with what justification I don't know, but again I haven't seen that Fruity got the same treatment. He, so far as I know, was not having an affair with Mosley.