Cornucopia Enterprises sell them for £40

http://www.cornucopia-enterprises.de/catalogue/flyer_norton.pdf

Watch out, I think that £40 is his 1997 price ! I can't believe he hasn't updated it for that long. Availability is not what the listings suggest either.

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...

I got mine from Cornucopia many years ago and it is top notch.

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.

Got S/H one from Cornucopia today, with post and vat £100

Ouch... that took a year to sort out, It's amazing how time flies.