We are still researching the company, Dewtron. As far as we know, the compamy started in 1964 and produced kits and some ready-made synths until the early 80s. They would supply a kit for a complete synth (such as the Gipsy) or modules of their own construction such as VCO's, VCA's, LFO's (which they calles 'Slo-Osc') filters etc. as well as the keyboards (which I think were imported from Italy).
One product which they seemed especially proud of was their 'Modumatrix'
system. This replaced the conventional patchboard routing (as in for example the VCS3) and consisted of individual single switches in plastic blocks (a bit like Lego if you know what that is!) which could be slotted together to make a large block of them; depending which switches were 'up' and which were 'down' determined the path the signal took from one side to the other.