A lot of machining work required Derek and substantial cost. Why not swap the clutch housing cover for a pulley type ( Neil Jarrett ) and fit a dynamo which you could then use to drive an electric winch through a battery, if you fit a dynostarter you will also get the benefit of electric start and your machine remains virtually original, alternatively you could sell your 5 and with the cost of the parts needed to convert it buy an MG6 .
Never the less it would make a challenging and interesting project if you do decide on the conversion.