When I got my 56, it came with a few bits and pieces. It had 2 door seals I had to fit. Unfortunately they were for the same door, passenger side. Fitted one up and it was great, door closes perfectly, no need to slam at all. Having read posts like this, I had heard of Midfifty hollow seal, so I bought one 2 weeks ago for my driver's door.
At first I had to slam it to shut it, but now it takes just a firm close. It will be interesting to see if it gets as good as the other door. Unfortunately the seals I got when I bought the 56 were not in a packet, so I do not know what brand they are but the one I fitted was great straight away. So someone out there makes good ones, just no one seems to know who. The Mid fifty ones seem like they will be alright, but no help to you unfortunately with your F1.
My old girl has the original look, which I do love. I would like to customise the body of my truck, but don't have the nerve to pull it apart for a significant custom rebuild. Long live the darkside and those with the courage to travel there.