Shula was very careful not to be condemnatory in public. So it was a disaster for her when she was misreported in the press, or rather Susan's bile was printed in a way which meant it got attributed to her, and also very unfair.
She stopped being a churchwarden (after asking Phil what she ought to do and taking his advice about owning up that she had spoken to the reporter, which was bad advice as it turned out) when Alan told her he could no longer trust her, in Spring of the year he got married, but went on going to St Stephens. It wasn't until he asked her as a lay preacher, which she and Mrs Antrobus both were, to come and consult with him about Christmas services that she came up against a Hindu statue in the vicarage and she'd had enough and went elsewhere for some years. Daniel was at the Cathedral School so she went there, which was more reasonable than it seemed because he wanted to go to services at the Cathedral.
Things like Usha deciding to take up bell-ringing in order to take that away from her had already happened that summer. Usha was vile to and about her, and also at her. And forgive me, but I don't think that religion is the same thing as race: not liking Usha's religion being part of the vicarage isn't racist, on that basis. She would probably have felt just as unhappy about anyone who wasn't a practising Christian as a vicar's wife, no matter what their ethnic origin.
Actually I think she was absolutely right about Usha's spirituality not being equal to Alan's: Alan is a professional Christian, goes to church every Sunday several times and so on, whereas when is the last time Usha even mentioned her faith at all? When she insisted that they had to get married twice, back in whatever year it was. She's not what I would call particularly observant!
(I remember it so because I felt very sorry for Shula, who was vilified for something that she hadn't done and would never in a million years have done, talk anonymously to the Press. She isn't my favourite person, but I dislike injustice of that sort. And she was miserable about it, and miserable about being unhappy about it and not being better and able to deal with it, which is a horrid way to feel.)