Righty ho! Waidmannsheil, Iowa 303 & Jorgen... I've been working away at the right hand feed ramp & success. Little by little I polished away the offending areas of metal and success.
I can now feed from the rotary magazine five rounds to the chamber successfully.

In truth I think a little more polishing is needed in one specific place. I notice the cartridge body now that it's positioning is a little more forward, there's some very slight 'trapping' between the ramp shoulder and the other side of the action. It is slight though and just a little more should make it perfect.

The photo's Iowa 303 & Jorgen posted/sent me were a great help & Waidmannsheil your success encouraged me on. I think in view of no logical explanation or visible reason why the jamming occurred, one just has to be 'brave' and proceed with caution polishing some metal away until the action does work properly once again.
Best wishes folks.
Cheers deeangeo

Pic of reshaped feed ramp in my MSch M1903

How it was before reshaping