Salut
Update: belts fitted.
Here are a couple of photos of what I've done:
Here you can see one of the plates and the square section bar welded to it.
Above is a general view of the bar in place and a harness attached - wrap around for the shoulders.
Above a detailed view. Gaffer tape used to stop the shoulder straps sliding along the tube.
And everything back together with Bubble Bum booster:
A few comments: base plates were bought from Sue Miller. The holes were enlarged to give a bit of play because the alignment wasn't perfect and it made fitting them a lot easier. The tunnel plates are a two-man job. One side had enough room - the other I had ease in with a hammer. Exterior plates are easy enough to fit - if you enlarge all the holes a little.
The pre-cut holes in the fibreglass back of the trims are not well aligned. I used the pre-cut holes (contact glue used to make trim good) in the tunnel. With a bit of shoving they were OK, but it takes a lot of attempts to find the thread for the belt bolts. Holes in the rear-quarter trim were not in the right place.
Bolts are 7/16 UNF 1.5 inches. You'll need a spacer too for all anchor points.
What I'd do different: shorten the bar so all fixing bolts would find a flat under surface and use the standard plate back - I had to use oversize washers. Maybe use 20 mm section bar - but the 16 mm I used doesn't flex at all. A better plate could be designed rather than using a standard rear seat plate.
What I think: I think my system is stronger than the Mick Miller 3-point system, but probably not as strong as the Spyder system. However my shoulder anchors are not screwed into welded bushes which could be a weak point.
Other things I did: removed +2S rear seats for +2 seats. Without my foldable-type +2S rear seats I reckon I gained at least an inch of legroom. To do that I had to cut away the rear lip at the rear of the quarter-trim. One side had enough excess black cloth to wrap around the back, the other is a little short but doesn't really show. If I find some similar material I might tidy that up. Also changed the front seats again for more legroom.
So, all in all 'No (Lotus) job is (too) small'.
@+
Vernon