I don't have a Rayburn, but I have a couple of MF stoves, one being a MK2 little Wenlock.
Before they screwed with the mix, she ran well on Maxibrite. She also likes Phurnacite (I have couple of tonne in stock for emergencies! Mum isn't allowed to touch it, she shovels it On as if it grows on trees!).
My coalman a couple of yrs ago recommended Multiheat and I've used that quite satisfactory by itself AND with wood. Coalman also says that there is a difference between heat rolled & cold cured. I look at the DEFRA smoke control site for suitable fuels, got paranoid actually comparing the ingredients and the %'s of different mixes!
Dad has a Deville boiler cooker and uses Burnwell Blend but DOESN'T like the new mix. He does however like Union nuggets as they don't clinker. There are certain fuels that yes, they belt out the heat, to me they are too high in the PetCoke!