As I seem to have killed off the Christmas Quiz I had better give the answer to my question.
The picture is of Winchester Chesil Signal Box most probably taken in 1943 shortly after it had been enlarged.
My father was signalman there during the first part of the war and took this and the following photograph.
I remember him telling me how he and my mother were able to see all the fires and bombing of Southampton and Portsmouth from the hills behind the box. On one occasion a German bomber came over the station and as it flew low over the box my father could see the front gunner looking down at him. Fortunately he did not open fire.
They lived in a company owned house very close to the box and my mother could whistle to him to let him know his dinner was ready which she would then take over to him.
Here is a picture taken before the box was extended.