Sizing guide - XS8-10 S10-12 M12-14 L14-16 XL16-18 (see measurements for more accurate details).
Laid flat and buttoned up across chest in cm XS50.5 S53 M55.5 L58 XL60.5
Length at front - XS64 S65 M66 L67 XL68
Length at rear - XS70 S71 M72 L73 XL74
Sleeve length - XS61 S62 M63 L64 XL65
Rae is size 10-12 wearing medium but can wear size small for a neater fit.