Soak the raisins in the liquor for 1 hour, reserving the liquor for the custard mix. Thinly slice loaf and butter ( this is optional, I don't always butter bread if using brioche, keeps calories down!).
Layer brioche in an oven dish scattering in the raisins and pieces of chocolate in between layers.
Make the custard by gently heating the milk and cream, add the reserved liquor and orange juice, add to the yolks and sugar whisking as you go.
Pour over brioche and transfer onto a baking tray, fill with boiling water 2/3rds up and place in a pre-heated oven set at 300F for 35-40 minutes After 20 mins brush on warmed marmalade and return to the oven to finish cooking.
If required you can finish under a hot broiler to caramelize marmalade. Serve with heavy cream.