Well,
Got my new Durites fitted without any major drama - The plastic rings needed a bit of fettling (as documented elsewhere), then the fun began!
The metal rings which clamp the light unit to the plastic ring were a tad rusty.
1 was fine, the other three fell apart into iron (oxide) filings
Luckilly, I have ignored all calls from Angie in the past when she said "Why are you keeping all that rubbish".
The chrome trim rings off a Dolly Sprint fit with a bit of adjustment to the mounting points, and held on with M4 bolts - no sweat - all back together and working.
Just need to get them aimed correctly now (job for the weekend!) - should be a piece of p*** now all the screws and bolts have been replaced with Stainless ones!
Just for info - the light units cost £26.41 inc VAT for the pair from a local supplier - 2 days to get them in.