Biggin Hill area?

Well done Beachbum,that took some finding. When I did inundated with info on the web.
Lets hope this one is easier. Where did I see this Gable End..

Well done grandarog, it is one of the Joss Bay sound mirrors.

One was carved into the Cliff and concrete faced, the other was a seperate structure.

By 1921 they were removed and the Technology moved down the Coast.

Platform to do with the Sound Mirrors at Joss Bay. Phoyo Andrew_Grantham.

"However, in 1918 the area became home to a research station that conducted a secret programme of acoustic trials under the guidance of Major Wiliam Sansome Tucker, an imaginative and ambitious advocate of sound as a military resource and tool of defence. Just north of the beach huts a station HQ would soon appear, resembling little more than a shed adorned with sandbags. The nearby cliffs would provide a well orientated catchment area for sound sources originating near northern France, and the stage would be set for a series of sonic experiments that ranged from the innovative to bizarre.

www.heritagegateway.org.uk/Gateway/Results_Single.aspx?uid=1479419&sort=2&rational=m&recordsperpage=60&maplat=51.38277548&maplong=1.44593468&mapisa=1000&mapist=os&mapilo=1.4459&mapila=51.3828&mapiloe=e&mapilan=n&mapios=TR397705&mapigrn=170550&mapigre=639750&mapipc=&resourceID=19191

Am I correct in thinking it is a military construction (going by the men in the photo) ?