FINALLY! I've removed the too-short old sleeves and sewn longer, new ones in and finished! Just in time too, as I am wearing this to the book signing in two weeks time, which means I really have to get a wriggle on with my new early 14th century belt to go with it.
I'm really pleased with the new sleeves. I think they're a little more snug on the forearms, which is what we see in manuscripts like the Manesse Codex and Luttrell Psalter and won't ride up on my arms with movement.
As for the belt... I've been so worried about putting the belt mounts onto the silk tablet-woven belt itself, but I found some little metal discs at the local bead shop and doll hospital which will be perfect. They were being sold as jewellery spacers, but they neatly fit over the posts of the belt mounts and with a bit of luck, I'll be able to peen the posts over.
I'm really looking forward to having the entire outfit completed, and the belt is the last piece!