Normal procedure with drum brakes is to back off the adjuster/s till the wheel turns very freely with no contact at all from the brakes.
The use of a puller is normally a recipe for disaster as the linings will stick to the drum and the springs and any other attachment device gets pulled apart. Not good.
I don't know the drum braked Morgan (except older three wheelers) but in your case, I'd hope the drum comes off without the wheel bearings. Even then, one can get the bearings apart without using a puller.
