https://www.walesonline.co.uk/news/wales-news/house-of-fraser-howells-cardiff-17288541Seems like a pretty damning list of past poor maintenance by HoF and their previous landlords, which means big problems in the here and now for the current owners.
I think what will happen is that the current owners will end up taking a big hit financially, and may need to sell on at a big loss. I would expect the development value to still exceed the cost of works - its just the current property/land is now effectively worthless.
Still at the very least it means big delays to any transformation plans, and the potential for a large and prominent building to sit empty and decaying for a considerable period of time.
Also, shouldn't the (newish) owners have done better surveying and due diligence on the purchase? How could these issues only be coming to light now?