I'd have said Large, Med, Med, Small.
But as Steph said, I'm guessing from how mad you are that they're not?
Itti's have stupid sizing anyways. I know Dawn's a chunky baby, but a Large fits Jayne's Lo who's like 8 months old! He is not 'large'
It's like New Look baby clothing. All their jeans are tiny skinny legs. Makes me mad...
I can just imagine some mums thinking "well, little Lambrini is 2 months old, but she doesn't fit in the 0-3 clothes. I'll have to put her on a diet!"
Ahem... Sorry for my rant there
But, yes, I've heard the SE's are smaller than the normal ones.