I made a pilgrimage the other day to the remains of the old Octel bromine works in Amlwch, Anglesey, which shut down over 20 years ago. Not much of the actual plant still stands, apart from a couple of concrete huts and the water tower, on which the WPS-2806 still stands. After a 30-second walk into the nearby playing field, the 2803 was in sight! Both units are visible from outside the fence, so there is no need to go on site. These sirens are likely to be taken down within the next few years and will probably never sound again, for the controller has likely been destroyed. Here's a couple of the pictures I took there:

Forever mourning the UK's WWII air raid sirens.