Civil Defence Corps Training Ground

As I was pouring over my collection of Healing maps, I discovered something I had never heard of before - the Civil Defence Corps - and they were training here in Healing! 

The above map shows the training ground - it is on what is now Poplar Park, specifically where the tennis courts. Wikipedia tells me that the Civil Defence Corps were active during the Cold War, and their aim was to assist civilians in the aftermath of a nuclear attack. They wore dark blue suits with berets. As I mentioned before, this site is not mentioned in any of my books, so there is no evidence of what occured here.