Not saying she hasn't but why do you assume to know where she shops, M&S are not the shop they used to be IMO and I haven't shopped there in ages so why assume she does? TBH she probably shops in better places than that with her salary. So what if she changes her sentance from 'going' to 'used to go', she is there to sell for QVC as are all the presenters. Hardly going to do much good for QVC if the presenters start prattling on about going to M&S the weekend to buy a jumper, never going to happen from any presenter of any of the channels, and I like to think as a viewer/customer I am able to decide what I think is good value and if I'm not sure then I will check elsewhere.
I would imagine that at some point all the presenters purchase something from the channels they work for if only as they probably get it at a lot better price than we do.