Thanks for the info, jayceebee,
I cannot say I ever dealt with them personally, as I was too young.
The shop I worked for at the time ended up with lots of the early 3V22, 23, 29 type heads brand new boxed, likewise 9K series tubes and others, now I don't know if that was an 'official' stock clearance sell-off as the factory was due to be demolished, or due to some 'insider trading',
this would have been around 1988-89 ish.
I believe Vista Electronics based at Wingate (Co. Durham) ended up with the re-gunning plant and re-heading jigs, Malc Scott reckoned they did, and this would make sense.
I dealt with Vista for many years, buying re-guns, heads and components.
Sadly Vista is no more either