Neither do we, but I wish Christmas were celebrated as Thanksgiving as - i.e., less commercial, more family-orientated.
Where I live, though, there are many Americans around - there is a large international school locally, and many of the rich American bankers who work in the City live out here - so the local supermarkets and shops do market it. It's probably one of the most American areas of England in that sense, so it's more noticeable than would otherwise be the case.