But is it a dress or overcoat...
And could it possibly be a Soldier in uniform, as the Somerset Light Infantry Barrick's are right next to the park.
Going back to the figure and assuming it's female, wouldn't the hang of the dress be wrong for a 1920's, as the 1920's was drop waist which hung in line with the body, this seems has though it's draped over other clothing, so could well be a coat!