Help me 🙏 Tesco baby boy clothing size

[nkubk]

My grandson is almost 10 months old, weighs 10 kg, and is about 71 cm tall.

Could you please help me choose the right size for Tesco and Sainsbury's baby clothes? Thank you!

If you look online each retailer will have a size guide. For example, this is on the Sainsbury’s TU clothing website. By 10m it appears it goes off height/length rather than weight.

Length is probably a better indicator of size at 10 months than weight. Personally I found Sainsbury's to run slightly bigger than Tesco. It also depends on whether they are in proportion, my daughter has a short torso and longer legs and arms. She used to outgrow clothes based on leg length. Now she's nearly 5 some of her t shirts are 2 sizes smaller than her leggings!
It might be worth asking mum and dad what size they are in/ need. My daughter is slow growing and was often in clothes beyond the height and weight limit. Also, if she's been in a size for a while I'll ask grandparents to buy clothes in the next size up so we get more wear out of their gifts, especially for clothes not specific for a season.