Indeed.. it's an engine out job as you can't drop the gearbox because of the chassis. In principle the concentric clutch is a good idea in that its mechanical force is directly and evenly applied with mechanical advantage to the clutch plate.
Its moving parts are really the bellows section which directly drives the thrust bearing so no strange wear problems from actuating levers and clutch forks and worse... bell housings! Now I can hear everyone saying that's ok until it goes wrong and to some extent there is truth in this but it was designed to outlast a clutch wear life and it will do this in the majority of cases. The thought behind this is if you need to change a clutch you change the concentric unit at the same time. Granted this is not always the case and some do fail but where Morgan is concerned they made it more difficult to do and removing both engine and gearbox as a unit is the best and safest option. Some cars with this fitment have no bleed option which is stupid for two reasons. Firstly it's hard to flush the dirty fluid from the concentric unit although it is really just a bag so you are not wearing piston parts as in traditional slave cylinders .
Secondly, they are notoriously difficult to bleed even when a bleed option is present and in this instant I would recommend a reverse bleed method. If this is you, feel free to contact me for further information as there are do's and don'ts. If you have the no bleed option I would suggest sucking out with a syringe all the dirty fluid from the reservoir. and replacing it annually as most of the dirt is produced by the clutch master cylinder and sits in the reservoir. It's not the best option if you had a choice but it's better than just leaving it to get totally black and contaminated and it also helps control its hydroscopic characteristics.