Hi MB,
That looks to be one of those odd ball colours that Rover used when production first moved to Eagle Farm from Thebarton in Adelaide just prior to them commissioning their new Powder Coating line. I will say that this green is a far nicer looking colour than their Kermit Green Powder Coat colour that we've all grown to dislike.
As such we wouldn't have any colour coding on hand to help you out on that one. My best advise is to get paint mixed up and colour matched prior to stripping the original paint off, also while doing that I would take the engine off and closely inspect the chassis rails for stress fractures before going too far as you may have to solve that issue prior to refinishing with new colour.
Cheers,
BB.
