Jim
Just been ferreting about in the garage and I found a Bond trim bolt, tried it on my one remaining piece of G trim and it is the one, see attachments
Possibly you are now sorted but I could send you this one (not the pound coin as well) which will give you a pattern so you can get some made, or just maybe I will find some more as I do recall having a bag of these somewhere, if I find them then they are yours since I have made an executive decision to stick with Marks A-D
Cheers
Nick