https://www.gomog.com/allmorgan/interior1.html#WATCHPOINT Yesterday, actually, made and fit the shoulder harness braces between the chassis and the anchor points at the top of the wheel arches. Coat of paint and drill the holes in the chassis today...
I have never seen that before. What is the logic?
To connect the shoulder belt anchor points to something more substantial than just the wooden wheel arches. When we got the car last year there were no belts at all, just the holes where they had previously been installed.
You are a wise and prudent man, 1854sailor. There was a time when Morgans (and other vehicles) did not have seat belts at all.
Then a very LONG period when they had to fit them by law. Then 3 rather than 2 pointers became mandatory, but no still no testing
was required. Laws enacted by politicians are not always wise. Sadly they, to my mind, made things worse in many cases.

Since our own accident 21 years ago
https://www.gomog.com/allmorgan/RearEndCollisionRisk.jpg I became more interested in
such things. I discovered, after interviewing other "crash test dummies" ;), that the top fitting post on the rear wings, merely rips the
wing off in a rear wing impact. That snapped the neck of the wife of a mogger. She was sitting on the left in an RHD environment
while touring Greece (IRRC) many years ago. With amateur racers and the same seat belts, their upper bodies pleat at the waist
lurch forward and their heads hit the windscreen.
The Factory, when crash tests became more comprehensive and affidavit compliance began to end, moved the top anchor all the way
through to the end of the chassis! But I find that very messy as it is long, obstructs access and it gets filthy.

So instead, with the help of some gurus, I use this metal strap, merely attaching it to the lower side of the rear wing seat belt these cars
already have. I and many others have been thankful for it for 100,000s of miles since. It is non-invasive and well within the skill level of
an amateur. I merely align the metal strap, easily made at home from any length of metal, on an angle rearward to the chassis so the
strap is the most effective.
Not much help if it goes straight down to the chassis. It is another trad area where a few minutes of costless work and no special parts can avoid tragedies.
Lorne