I got so fed up with it yesterday that I decided to zigzag the remaining few shapes just to get it done. I'm not altogether happy with this solution, as if you do small zigzags, they make a dense edge to the join, but if they're bigger, I'm not confident that they'll hold. Ah well, I only had a few to do, and it got it into a manageable shape.
After a couple of borders, it looks quite pretty. (Just look how the yellow and blue borders have brought the yellow and blue nicely to the fore and pulled it together quite satisfactorily.)
But, I am heartily sick of these hexagons, which were given to me by the daughter of a lady who made them in the 1960s and 70s. She wanted them to go to a good home, and if you feel like you could give them the respect and love they deserve, please contact me and I'll gladly send you the whole blooming lot!