Hi Paul As no one else has answered, I'll jump in. Looking at the parts diagrams the mkI/II and III bumpers look the same overall shape but there are some fundamental differences, principally the chassis cutouts in the top of the early ones (which you could probably make, given that they'd be behind the over-riders), and the end support brackets which on the mkII are fixed by chromed coach bolts about 6 inches in, and on the mkIII by a captive nut assembly at the tip. Again you could probably drill and file the coachbolt hole (note it has flats) but of course in both cases you'd be breaking through the chroming and encouraging rust to start. And I cant vouch for the hole spacings matching up, not having a mkIII bumper to hand. Still my guess is that it's doable. I stress again this is all only guesswork on my part, if anyone better better informed than me wants to dive in, please do. Personally I'd bite the bullet and buy the one remaining MkII one Rimmers say they have have in stock, (806956) albeit at an eyewatering 450 quid. A lot cheaper on Paddocks site , but they are out of stock. Might be worth talking to them though.