S   M   L
Bust 15.5-16" 16.5-17" 17.5-18"
Waist 13" 14" 15"
Hip 18.5" 19.5 20.5"
Length 33" 33.5" 34"

*Model is 1.70m, UK 4/6 (PTP15", Waist 11.5", Hips 16.5") wears size S

If you are in between sizes for bust, it is best recommended to size down. 
If you are in between sizes for waist, it is best recommended to size up. 

*In between sizes refers to your measurements falling between 2 sizes, example size S & M.