I hadn't heard of aftermarket remotes, either. However, you can get your remote repaired by a mob in the UK. They can also clone your remote. I'll try to find their details.
I bought a spare BECM from a fellow forum member. You might try Andrew E on this forum. He wrecks P38As and had a lockset/BECM for sale.
You can get them reprogrammed by Lee Bourgeois on Labtronx in Mittagong NSW LAB Electronics Electronics for the Automotive Industry. (Rupert, do you reprogram ECMs?)

