The note on this site shows that the original planning application was for Demolition and construction (with later change of plans). That the demolition has been done means the expiry date on the original permission is no longer relevant as the development has begun (even if so far that is just the demolition), and the site last time I was in town had those sort of metal fences you get around building sites. Brownfield might be an option, though I think of that more where there isn't approved plans in place.