Ken is a good bloke.
I mentioned this forum and he has kindly provided some info
To answer a few of the questions on the board.
Im a 73 years young (DOB 19/9/36)
I was still managing bands in 1960, i became Jims service engineer in 1962
The offset chassis was an experiment i tried later on.
There are many things to give the dating away. From the box design and materials, how the chassis was cut, importantly what compnents were used. But the most common way is from the serial numbers. As from 1963 i started numbering them starting from 1000.
Hence this one having no serial numbers predates them all. As also stated the number one chassis in the factorty even has a serial number of one. And this has been valued far far greater than what i am asking for this.
This price has been suggested by Marshalls themselves today at the factory.
If anyone has any general questions i will be happy to answer where i can
kind regards
Ken