Agree that Miranda isn’t that interested in Christianity and is certainly nowhere near converting over the Christmas play. I just think AF wasn’t that interested in portraying Judaism in much detail.
She’d converted by then, and was clearly hugely invested in being an anti-Vatican II trad Catholic, and in exploring Patrick’s faith, his (rather tiresome) pride in his recusant family heritage and his clashes with his progressive school etc.
And in Nicola’s confused attraction to Mass in the Merricks’ chapel, and in the various Marlows’ different attitudes to their own Anglicanism, from Ann’s devoutness, Pam skipping ASB services, Lawrie thinking everyone thinks Jesus and co are imaginary, Rowan saying to Patrick that she sometimes believes and sometimes doesn’t ‘for quite long stretches’ etc etc. Plus the opportunities for religious theatre given by the Play and the carol service.
Though I am always interested in the fact that AF sketches in more than one reference to anti-semitism (Miranda talking about inviting people home in the holidays and them suddenly finding they can’t come because their mother’s going out, and the ‘common little soul with the perm and the Jaguar’ who never stops saying ‘Whose father’s a rich Jew, then?’), but we never get to see that in action. That ‘common’ girl (whose name escapes me? Yvonne?) never makes an explicit anti-Semitic remark in front of the reader, though we see her being explicitly unpleasant, on the first day of term, about Miranda’s wealth, by remarks about the ‘exclusive model’ (the green and black dress Miranda travelled to school in because the au pair packed her uniform in her trunk), and the obvious cost of the Disaster she later gives to Nicola.
(Incidentally, does this mean Miranda returned to school in a couture outfit?)