Okay you guys are very clever and resourceful indeed!
I had thought of taking the lip and fitting it to my el cheapo double bubble, but the lip is about 2 inches wider than the screen and of course screen a lot more "bubbly" (curved) than the lip. I didn't think the MRA screen was particularly good anyway, and if the lip doesn't match the screen, I really doubt if that's going to work too well. I am fairly happy with the el cheapo screen + decent helmet (Schuberth) combination.
Also, Noggy helped me out with a radiator hose when I really needed it - so I am just passing it on.
Anyway, Sinto got to me first, and Paulfzs second. Since both of yous only wanted the lip part alone, I have left the hinges to soak on WD40, just to be on the safe side. I will update how it goes.