I was out looking for a real Xmas tree around 2 metres tall for outside the house and everywhere seemed to be around £35-£40 for 'Nordman Fir' Xmas trees.
Popped in to Focus with the missus and she noticed a sign which IIRC, stated 'Nordman Fir' Xmas trees between 1.7m and 2.2m were 50% off (normally £24.99).
Well I picked up a £24.99 tree (didn't check what it was at the time) and took it to the checkout and true enough, it was £12.50.
I noticed the label later on and it the tree I picked was called a 'Glisten' (whatever that is), so maybe all the £24.99 trees are half price.
Not sure if it is nationwide, but the label was a 'proper' promotion sign, so may well be.