Started off at £16.99 and as the 25th draws closer they've dropped to £12.99, £9.99 and now scanning at £6.99.
Box is still marked £12.99 and shelf still marked £9.99 in the Bangor store. They had loads and loads left. Last week though, I was in the much larger Holyhead store and they'd sold all but one, so try your luck.
The mains plug is of course indoor only. You then have 5 metres of cable before the lights start. The button to change how they flash is on the mains plug. Much better than the Home Bargains lights I bought last week which had the control button in it's own, supposedly waterproof, unit right where the lights start i.e. outside. Of course for some that might be preferable if the socket is in an awkward position.
I bought warm white and would assume cool white (which they had many more boxes of) are also reduced, as they've always been reduced together so far. There may be similar reductions on other lights as they seemed to have plenty of everything.
Photo with receipt in first comment for the doubters.