S   M   L
PTP
16" 17" 18"
Waist 13" 14" 15"
Hip 18.5" 19.5" 20.5"
Rise 12.5" 13" 13.5"
Length  39" 39.5" 40"

*Model (wearing Dark Mustard Print) is 1.70m, UK 4/6 (PTP15", Waist 11.5", Hips 16.5") wears size S.
*Model (wearing Sage) is 1.64m, UK 6 and wears size S.

If you are in between sizes for PTP/waist/hip, it is best recommended to size up. 

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