Cornucopia got back to me, said they can make one for £60. £30 deposit and wait a few months. They stopped listing them years ago due to lack of demand.
But things have moved on since then...
Your bike looks really good Sam
Much better than the one recently featured from the UK National Museum. That was over restored and missing parts. I'm not going to restore mine, just run it in it's early '50s time capsule form as it was purchased demobbed from Pride and Clarke of London. It all works properly saving work to be done on the lights, but I doubt that will take much. I need the sump guard as I want to run it at this year's Arbuthnot trial, across Salisbury Plain near Stonehenge.