Write what you know. That's what they tell you. I suppose that what this boils down to is, either write out of your experience, or do some research. Some writers adore research. They love mooching about libraries or googling the bejasus out of things. Researching means you can put off the evil day when you actually have to start writing the novel. I am not one of those writers. I spent seven years grubbing about in 17th century Quaker pamphlets trying to write a doctorate. That's quite enough research for one lifetime, thank you very much.
So I'm a write-out-of-experience type of novelist. And what I have a lot of experience of is the C of E. But there's an even more important advice to bear in mind: avoid libel writs. This is where the research-heavy historical novel is a safer bet. I could write whatever fictional nonsense I liked about James Naylor or George Fox without getting sued, because they are long dead. But writing about the C of E is a little more fraught.
My best strategy is to assert loudly that I am writing FICTION. Acts and Omissions is set in the FICTIONAL diocese of Lindchester. Look it up: there's no such place. But if I were to populate my 'fictional' diocese with thumbnail sketches of thinly disguised and easily identifiable bishops and canons, I might still fall foul of our country's fearsome libel laws. So I make as sure as I can that my characters are COMPLETELY MADE UP, yet at the same time, very realistic. I'm well aware that many readers will assume I'm lying, and that I'm actually writing a roman a clef. (That's 'a novel about real life, overlaid with a façade of fiction', to save you the bother of googling it.)
What can I say, other than I'm really honestly not doing that? I take great pains to avoid any obvious similarities to real people. For example, the precentor in my cathedral is called Giles Littlechild. He's a character I've had ready and waiting since about 1986. I first encountered him (in my head) before he was ordained, even; but have never used him in a novel. Until very recently he was called Miles Littlechild. But then we moved to Liverpool, and what do I find? We have a precentor called Myles. So despite the fact that my wholly imaginary precentor is nothing like my very lovely neighbour, I have changed his name.
What I really dread, of course, is that I accidentally hit upon something true which reads like some shocking revelation by an author writing what she knows. From all such mishaps, Good Lord, deliver us.