Photo courtesy of Elizabeth Ride, from her private collection:
I was looking at your site about Topees, and thought you might like to see the attached photo: 'Topees, Summer 1931'. The strap across the brim was originally a chin-strap. The button on top was only decorative I think, but may have had a function on the original topees.
The children are my brother David and myself taken at a house in University Path, which no longer exists but was a continuation of Lyttleton Road. Here is a photo of the Compound pre-war with the three semi-detached Staff houses on University Path at the top. In those days, we were shifted around the University properties as we came back from Leave, so I cannot say which one it was, but it looks like No 1 to me.
What David is showing me I do not know, but he was a great collector of bugs and beetles, so that could be the answer.