That's very interesting -- over £700 for the one sold and the other already more than £600 with 3 days to go and that's in their country of origin. They are even rarer this side of the pond.
I see the 1975 F was withdrawn from sale.
The seller says "First my apologies if your bid was cancelled. I received so many questions, I felt it was important to get more history, test this item and relist with as much information as possible. Thank you for looking"