From past experience I think that you will be lucky to find any old deserted factories in England - most areas have been redeveloped in the 80s/90s and very little inner city industrial areas have been left untouched. The only thoughts I can suggest are:
Bankside Power station, London - converted into the Tate Modern Art Museum
Battersea Power Station, London - supposedly protected, but still empty and undeveloped.
Millenium Mills, Docklands, London - awaiting redevelopment as part of the Bekton redevelopment area, though access is very difficult.
Someone may be able to suggest locations around Leeds, Yorkshire or perhaps around Manchester, Lancshire - this was part of the industrial heartland in the industrial revolution, though many of the original mills had been removed last time I looked.
There is an open air museum in Beamish which preserves a living industrial revolution town and mine. Details here:Beamish