The power of advertising is a scary thing if you’ve got children. I realised this the day my three-year-old approached me while I was scrubbing the sink one day and declared: ‘Mummy, you need some Cillit Bang. Just rub it in and, BANG! The dirt is gone!’ Advertisers know that children are like sponges when it comes to retaining information. And at this time of year, when parents are frantically trying to work out what Santa might do well to bring down the chimney, it’s ultima