The boat you are talking about wasn't being sold by Norton Canes, it was a private sale by the owner, who at the time was a fitter at NC.
It was quite a bit more than just a sailaway, the boat had been installed with a Marine Gardner 2LW, there was a back cabin, which had been scumbled and decorated, the boat had been gritblasted and coach painted, the main cabin space had been sprafoamed and all wiring looms were in place, the price also included a Heritage Range and all the lining out materials.
So quite how you can publicly comment on the price of a builders boats upon a private boat sale, I'm not sure.