So its been going for at least 8 years. That's quite long in terms of product lifespan, at least with Chinese manufacturers.
That's Thurlby Thandar Instruments Ltd of Huntingdon, Cambridgeshire. That's a very old British firm - they were around back in the 70s as far as I can recall. Still do all their manufacturing and design in the UK.
Yup, had a quick look, started back in the 70s. From their website:
Company History (TTi)
The origins of Thurlby Thandar instruments Ltd date from the late 1970s when two separate companies, Thurlby Electronics Ltd. and Thandar Electronics Ltd. were both designing and manufacturing electronic test equipment within close proximity at St. Ives in Cambridgeshire, England. Through the 1980s, Thurlby specialized in bench power supplies, high resolution multimeters and digital storage units; whilst Thandar specialized in function generators, frequency counters and logic analysers. In 1989 the two companies were merged into a new organization - Thurlby Thandar Instruments Ltd. and located to larger premises in nearby Huntingdon. Since that date the product ranges have been expanded and new product areas developed including arbitrary waveform generators, RF test equipment, Current measurement probes, Power Analysers and component bridges. All models are now sold under the Aim-TTi brand. Today Thurlby Thandar Instruments Ltd is one of the foremost producers of general purpose electronic test instruments and laboratory power supplies in Europe, selling products in over fifty countries.
I've a vague recollection that Thandar had some relationship to Sinclair Radionics, either started by people who used to work for Clive Sinclair or had some of their products badged by Sinclair. I used to know a couple of people who worked for Sinclair and probably heard it from them.