Archie is 8, 130cm tall and wears size 8-9Y
Harriet is 4, is 103cm tall and wears size 4-5Y
 
Garment measurements by size (approx):
Size (cm) 2-3Y 4-5Y 6-7Y 8-9Y
Length 20 22.5 25 27
Front Waist 20.4 23 24 26.5