I found a solution - unplug from mains, remove button cell (backup) battery from unit and leave it 20 mins.

When you plug it back in the unit will have reset and will scan for stations and obtain the time/date. Reinsert the backup batttery and the unit should work again (mine did).

Not sure what caused this freeze - suspect the DAB radio got stuck on a station with a weak signal and this caused some sort of software error.

My "solution" is somewhat flawed - yes it resets the unit, but there's an underlying problem with the radio tuner that keeps recurring - since purchase at Xmas, i've had to reset on countless occasions. Today while reprogramming the presets and alarms having reset after yet another freeze, it froze again. This is not satisfactory, so it's going to the Sonycentre for replacement.

This product is not fit for purpose! Shame I'd expected better from Sony

I too have the same problem, I am on my 2nd radio. 1st one took 8 months for the problem to come to light, 2nd one took only 1.5 months! Why should you need to constantly keep taking out the battery to get the thing to work surely with all of their technology this sort of thing would be something you did in the good old days! Really really disappointed in Sony as the sound quality when it works is brilliant.