DS is an age 3-4 on his tops, but he is actually still fitting his 18-24mo trousers in length .
It's snowing here today (yay!), and he does have waterproof trousers and coat which are fine for rainy weather, but I'd like to have an all-in-one so that there isn't a gap for when he rolls about - preferably sized so that that I can stick his normal jacket or thick jumper on underneath.
And, given he's due a growth spurt... the cheaper the better naturally!
I was going to suggest a Spotty Otter Chillibug, but guess that's out of budget. DS (similar size to yours given clothes sizes) is currently wearing an age 2 chillibug - no need for a jacket underneath. There might be some on ebay?