@Finnkai Subsequent to my post above, I discovered a video on YouTube which identified the source of the problem - 2 faulty capacitors. I purchased a pack of replacements for less than £10 and have...

I have now had 4 of these devices fail with the "no lights" problem - i.e. not even the power light shows when you plug them in and the reset/link button doesn't do anything to change this. I have...