Spectrum Communications is run by Tony Nailer, assisted by his wife Jean.
He's been in business since 1981 serving the amateur radio/CB/SWL community.
He became a long-standing and respected author with PW in 2004, developing new projects which featured in the excellent 'Doing It By Design' series. He authored another PW series in 2005 entitled 'Technical For The Terrified' and parted company with PW in 2017 following the change of ownership of PW. He's still very much in business selling kits, ready made equipment, aerials, aerial traps, and components, (including those for the Mini-Mod project).
Long standing amateurs may recall G2DYM Aerials, run by Richard Benham-Holman G2DYM, which Tony purchased in 2006. Also, in 2011 Tony purchased Garex Electronics, run by Peter Longhurst G3ZVI. He's still very much in business so you might wish to contact him.
His website is here:
http://www.spectrumcomms.co.uk/
You can email him directly with technical queries at:
g4cfy@talktalk.net
Hope that might help.
(I'm not his PR manager by the way - I just think he's one of the few remaining proprietors of small firms who isn't just a 'box shifter' but has a genuine interest in serving and keeping alive the remnants of what was once a technical, experimental and constructional hobby).