Not totally surprised. It's ridiculously over-priced, and they have only survived as long as they have because of other businesses having small 'units' inside there... Eg, Chanel...
As a few other posters have said, I cannot remember the last time I went in there. Literally, not even this decade. Maybe not even the last; could be 20 years.
House of Fraser is the same, over-priced and dated, and people can buy cheaper stuff elsewhere. For cheaper clothes for example... Primark, and Peacocks. And supermarkets sell cheaper, decent clothes too... Sainbury's Morrisons, Asda, and Tesco sell pretty good clothes. (And are also good for all your foodstuffs and consumables, along with Aldi and Lidl and Iceland!) And Wilkos and Home Bargains and B & M are great for almost everything else
Debenhams, and House of Fraser, along with WH Smiths and Marks and Spencer, need consigning to the history books. They haven't moved with the times, they are all overpriced, no-one I know ever goes into any of them -- or if they do it's very rarely.
Although it's a shame, and the end of an era etc, times move on, and sadly, the high street giants that have ruled for so many years, and charged astronomical prices for stuff we now KNOW should have been cheaper, are crashing and burning. (Thanks to much cheaper stores, and the companies on the internet... Amazon, Ebay, ASOS etc...
I am not glad - but I am not sorry that these stores are all closing down. Even Woolies used to be one of the best shops on the high street, and I used to virtually live in there, especially coming up to Christmas, but during the last 7-8 years of its life, it became overpriced and drab. Same with WH Smiths. That used to be a great store, but has gone to shit this past decade. That will be next. Then M & S probably.