It is the entrance to the Strand, at Gillingham Green. I think it stood approximately where the sailing club yard now is. Francis Frith has a photo of it from 1955 which makes interesting viewing.
DTT
You have it Dave
This was taken just weeks before it was demolished and I've included the more obvious view towards the entrance to the Strand that was taken at the same time; as well as the tradition view in its heyday. And although now a car park opposite it was for years the paddling pool and boating lake.
Ive lived in Cornwall for 40 years and my kids and their kids are surrounded by the best beaches, etc that you could wish for. Yet whenever we visit Kent its the same refrain 'can we go to the Strand!' My mother used to go their as a kid in the 1920s; me in the 50s, and nearly a century later my grandkids will be going next year in the 2020s.