A quick Google on CFS Massett gave:
https://en.wikipedia.org/wiki/CFS_Masset
https://www.google.com/search?q=cfs+...53949244&vet=1
https://www.101nisquadron.org/wwii-r...tation-masset/
I don't have any specific information to back this but suspect that given the Wiki statement that it is a signals intercept station, the elephant cage may be a form of antenna.
On edit,
http://www.jproc.ca/rrp/masset.html describes the structure as an antenna.