This model was built by ‘D. Sperrin’, but little more is known about it. The Sperrin Fuzz Box was advertised various times during 1966, and was being manufactured in Southport, then in Lancashire (now Merseyside).
The units may have been built by Dave Sperrin, who manufactured mixing desks for DJs in Southport, during the 1980s.
I would be delighted to hear from anybody with any knowledge of ‘D. Sperrin’ and/or their fuzz boxes.