A range of archive material on Warley Hospital (which will hopefully one day form part of a dedicated site).
SEAX archive (colour)
These photographs are just a sample of those kept at the Essex Records Office. There are hundreds more in the archive, some of which are viewable online, others only in person. It represents the most complete source of images of the hospital in use.
Some of these images were taken, I believe, in 1999 by Adam Garwood and come from the Essex County Council Report Essex Hospitals 1800-1948. A Study of their History, Design and Architecture
Getty Images (date and photographer unknown)
These remarkable images are from the Getty Images database, though the name of the photographer and precise date of the images are unclear. The date is given as 2000, but this may simply be when were added to the database; and based on the decor and clothing could conceivably have been taken at any point in the 20 years before this..
SEAX Archive (black and white)
Among the many buildings here are Centenary Hall, F Block, the Nurses' Home, Occupational Therapy, and, of course, the main building. The wide-angle view of the hospital was taken from the railway embankment and over the top of the hospital cottages.
Brentwood Library (images deposited in a folder by an anonymous benefactor)
Press Cuttings (click on images for larger version)
Aerial Photos
Postcards
Miscellaneous images (sources unknown/forgotten)
The sepia photograph and postcard above show, I think, the original hall of the main building.