Girlguiding Cornwall have 3 old Girl Guide Association belts for sale.
 
Belt 1 -  This belt has solid raised trefoils in each corner. This design continued in use until the late 1960s.
Belt 2 and 3 - Dates from around 1930's. During World War 2, a different style of belt clasp was available, which wasn’t as deep, and had a slide-through style.