I'm very fond of Mr Merrick too, and I think the cynicism of plausible deniability is out of character for him at home (in the House might be another matter). There is the possibility that pleasant as he seems in other matters, his sexual mores are antediluvian in their cleaving to the double standard; or, (my favoured explanation) that it's one of those areas in which his class trumps his Catholicism, as it were: there's something dreadfully petit bourgeois about an interest in sexual morality (roughly, it's talking about one's insides) and the thing is to adopt a gentlemanly indifference. Which is, I suppose, just another form of plausible deniability.

I've just skipped ahead and read his conversation with Patrick about Ginty (Patrick refers to what Sayers calls 'The Vestibule of the Futile' in Inferno, btw; I've always loved that phrase). I have to say I've always read it, perhaps without much supporting evidence, as Anthony talking about Ginty's sexual future. He sees her as someone bound by her beauty to the conventional ('unspectacular') role of either madonna or whore. Patrick misunderstands him and thinks he's talking about her character as a whole ('How devastating') and Mr Merrick's 'It wasn't meant to be,' is an acknowledgement of the restricted sense in which he was using 'good' and 'bad'.