I don't know anything but I just checked the hotel in Athens today and saw a few sale prices.
A few weeks ago I checked other places and couldn't find any rooms on sale
( and I checked the whole of June and July ).
So I am assuming that the sale is still on but that the rooms set aside for wintersale have been sold out along the way in some hotels.
What I have also noticed with this sale is the lack of rooms on sale on weekdays in the summer holiday. Last year a lot of hotels in Europe extended the weekend sale to weekdays in summer.
Add : just noticed that you asked specifically about UK, sorry.
I did look at hotels in London a little while ago. I looked for July and whereas I don't remember details, I know I found them horrendously expensive, so probably no rooms on sale even then ( 2-3 weeks ago ).