Doing a little bit of an investigate on my own at the moment, and I've found a few companies who might be able to help. No prices yet but there is an indication of a minimum run of 50 per side - and looking at the worst case I can find anywhere online (£100 per seal) would be a £10k investment. Not good.
However, I see that the front quarterlights that the Stag Owners club do are for sale for £34 the pair. If that's the sort of price we'd be looking at then it's a lot more possible.
https://socspares.co.uk/store/25-body-seals-rubbers?p=2
I emailed the company that did the seals for the Stag Owner's Club but no answer as yet. I'll try to follow up in a couple of days to see if they can help.
Here's who I've approached so far:
J. Coker (
www.j-coker.co.uk) - Did the Stag ones, no answer yet
C O H Baines (
https://www.coh-baines.co.uk/) - minimum 50 per piece, waiting for an idea of price
Fairham Mouldings (
www.fairham.com) - waiting for pricing info
Edgeware Motor Rubber (
www.rubbertrim.co.uk) - said no
Techmould (
www.techmould.co.uk) awaiting reply
The other thing that sprang to mind is 3D printing. I'm aware that you can't do proper rubber but there are rubber-like materials that may do the job, especially since it would only need to be flexible once to get the glass in. A company like this one:
https://www.3d-alchemy.co.uk/3d-printing-in-rubber.html
has the capability to make something big enough, but it would require a CAD model of the seal. That looks like a tough job especially since any seal we have now won't be quite the right shape or size compared to the original. I wonder whether the engineering drawings would be available at BMIHT? If I could get scans of those it would even be within
my CAD skillset to digitise them.