A small company of 5 guys, doing exclusively MSX titles. They started because they had the advantage of having knowledge of the MSX system at an early stage, probably because they had good contacts with Philips via Mick Rouse (who was the tech lead).
They brought the "Softcard" to the market (similar to the BeeCard in Japan, marketed by Hudson Soft): a credit-card like cartridge game. This was done by Mike Hall who also worked for Electric Software - he was the salesman, and the 'entrepeneur'.
The company was part of GST (General Systems Technologies), owned by Jeff Fenton.
Developers: Mick Rouse, Paul Johnson (he provided most of this info, thanks!), Andy Eltis, Jake Dowding and a Graham Conduit.
Birth- and death years are still an estimate.
The MSX SoftCard Adapter was also advertised by Reis-Ware Gmbh in Germany, but no known Reis-Ware SoftCard products exist.