cee-dee wrote: "...I thought the idea of advertising was "show off" products and persuade the viewer to visit the store and buy. The current bunch of elaborate adverts look more like adverts for the people that made/produced them."

You've nailed it. The adverts are 'tradition' now. Those producing the adverts (their department is called Christmas Replays Are Patronising) must spend their large budget otherwise they won't receive the same budget next year.

It's also an 'arms race' for rival company execs: "My advert's better than yours, ner ner ner ner ner." (How do you spell that childish sing-song taunt?!)

Next year companies could try scaling it back or have no advert at all, and see if it affects sales. But of course, in this 'arms race' no one wants to be the first to "blink".  That's also why we're doomed to the DFS sale for eternity.