Do you read the lines in any particular accent?

My MC is a Bristolian who picks up some Yorkshire when he's staying with those grandparents.

Penny is canonically some kind of Londoner and I imagine Jae to be one too; he's too well-connected to be from the middle of nowhere. Tulip as well, since her parents are at the Ministry.

The wiki used to list Ben as being from Newcastle; it doesn't anymore and I don't think it's canon, but he'll always be a Geordie to me, although his accent likely softened over the years. The idea of his early personality and dialogue sounding like Jade Thirlwall is a fantastic contrast.

The Pride of Portree thing makes me assume Andre has a Hebridean accent. Scottish, anyway.

I always imagined Badeea having a Welsh accent, based on nothing. I think of Rowan and Barnaby as sounding Midlands-ish, same reasoning.

Ismelda strikes me as a total Brummie.

Merula is the one I can't place. I feel like she could be from literally anywhere and it would work for her character.