have never bought from monsoon for the children, but we have a wedding and i have a linen waistcoat and trousers for ds on watch on ebay. he's 4, 5 in may, the wedding is in may, the clothes on ebay are age 3-4, do they come up small or big? ds is small for his age and slightly built, so am wondering if we can get away with age 3-4 or should i hold out for size age?