Keith,
There is a large Cannon situated in the " Fairy Glen " Douglas when you
enter the Glen from the Promenade end up Summerhill Glen Road, could this be
the Cannon in your picture?
It has been there since I was a child in the 1950's where it overlooks the
sea, then behind the cannon there was a small snack/ice cream bar for small
refreshments to complete the wonderful walk down from the top of the glen.
Kindest Regards,
Carol Lloyd nee SHIRLEY