I saw this promotion in store at Boots Cribbs Causeway, Bristol. They don't have any on the website.
The 100ml EDT was £21 and came with a free DNKY body wash while the 50ml was over £30. I asked the checkout assistant why it was so cheap and she told me that Boots were trying to make space for new fragrances and therefore clearing out selected 100ml bottles. She told me that this was nationwide for stores that stock this particular fragrance.