TW made some transistor converters for 2m and 4m but at the moment I have not been able to find any photographs of these units. Some information is shown on the TW leaflet that may be found here.
Adverts around May 1964 referred to a 2m transistor converter (size 1” x 1” x 3”) that used Philco transistors with available I.F.s being 4-6, 14-16 and 24-26 MHz. The same advert also referred to a similar 4m transistor converter with an I.F. of 1.820-2.020MHz. Both were priced a 9gns.
A later advert in December 1964 simply referred to a TW Transistor Converter (2N2360) again priced at 9gns .