Microtext were originally based at 7, Birdlip Close, Horndean, Hampshire but are now at 3 Rose Hill, Lovedean, Waterlooville, Hampshire.
As well as the Teletext Adaptor and Tuner for the CPC range of computers, they also made the market leading (at the time) adapter for Micro$oft Windows in the early 90s.
They still do manufacture a Windows Teletext decoder but, with the country going digital, this is now of limited usefulness (presumably).
They now provide computer maintenance and web design services - according to their web-site at: http://www.microtext.co.uk/