Looking at the pictures on Bonhams:
The rear mudguard is shocking, looks like its been painted over the top of rust, same for the dash panel, the wiring looks amateur and is attatched to the frame with electrical tape.
There are plenty of new shiny bits, too many IMHO for what is supposed to be cherished one family bike, that has then been restored. The original stuff looks like its been restored on the cheap, it makes you wonder where else corners have been cut.
I think you'd be better with something scruffy that doesn't look like it might be hiding untold woes.
Kev, I'm looking forward to this, I was thinking of the same thing for my next project. good luck.