Football and flags

A couple of people have pointed out some of the ways that people decorate their houses. From hanging bits of polyester out of the window to sprucing up their gardens. Personally I prefer a few flowers to flags but watching the football they were showing clips of England playing in the world cup 8 years ago and the majority of the supporters had the Union Jack.
Now i know that technically the St George's flag is correct because we haven't fielded a UK team but when did we start to pick up on the SGF rather than the UJ? Also I can't help but think that the UJ looks so much more patriotic and English than the SGF which I think has just suffered at the hands of Sun readers and the BNP over the years. the UJ makes me think of bunting and home made lemonade and waving the flag at the Queen! If she ever does a tour of Plumstead I shall get a UJ hanging out of my window...
Also I wonder how people can get flags twice the size of their windows but they don't seem to be able to manage to get net curtains or bits of sheet to fit and have to resort to stretching them across the window...