A lighting 3 pin transformer has failed and Googling "TN20UK" got me a
Google thwap (or whatever its called) - one result - but not it.

Its marked 240V 50 Hz
12v 1.67A-20VA

maker looks like TECNE TN20UK

Google shows me lots of things that are not it, I'm guessing somebody
here (he hopes) can point me to it?
--
Mike