Crowds on Tonbridge Castle Lawn

Being part of a family that has lived a number of generations in Tonbridge I often come across old photographs taken in the town. 

The black and white image below is of an event that drew a large crowd on the Castle Lawn.  The clothes seem to be pre-war, and probably 1920's to middle 1930's, as when zooming in on figures in the foreground I noticed a number of women wearing cloche hats.  These came into fashion in the 1920's and were obsolete by 1933/4. Close-ups on the crowd standing on the raised area directly beneath the castle seem to show some kind of ceremony taking place facing the onlookers.

Can anyone help?

Tonbridge Castle Lawn