As you'd expect it was not a success in the end:

> Supply exceeded demand, and 12,000 units were left unsold until they were sold off cheaply. This resulted in a £480,000 loss for Sinclair. Sir Clive Sinclair was certain that the TV1B model released in 1978 would be more successful, but sales were disappointing.

(https://en.wikipedia.org/wiki/Sinclair_Radionics#Portable_te...)

His later TV was more interesting in design but not any more successful:

https://en.wikipedia.org/wiki/TV80 http://rk.nvg.ntnu.no/sinclair/televisions/tv80.htm