Don't you take a close look at it before you take a £1300 item with you?
I would think that with large items like TVs most people don't open the box and check it out before they purchase the product and I don't think the store would want you opening and plugging the TV in on their selling floor before taking it home. Most stores understand that there can be something wrong when you take it home and open the box and would rather chance that than have everyone opening their boxes and unwrapping the TVs putting batteries in the channel changers so they can try them before purchasing. Stores know that this would be a nightmare for them. However if Comet doesn't handle her problem I think it would be a public service stand in the electronics deparment and inform customer that they need to do just that before they buy.