Wow Graham - great chairs!
Care to share the joinery used? Is is half lapped, and pegged (seat to frame)? What about the joints between the lower and upper seat sections?
Are there plans available? I haven't googled the attribution you provided.
@Henry W - the domino figured heavily into the build for me. One variation I made from the original plans was to lap the legs and chair sides instead of using dominos. I added small dowels for design more than strength, as there’s a whole lot of face grain contact there.
As @Jeff mentioned, plans are available digitally on Shaun Boyd’s site - and there’s also an option for him to send 1/2” MDF templates as well.
@gamiller3rd - I don’t have those exact measurements, but I’ll say its a deep seat. Definitely needs cushions in my opinion...