Wide fit wellies.. does anywhere stock them?!

My 20 month old boy has size 5 (G) feet and I really struggle to find him trendy suitable footwear. I have the same 3 pairs of Next trainers as they fit him really nicely, I have tried some others from Next but there’s no give and his foot wouldn’t even go in. I have just come across start- rite shoes and I have ordered a pair of trainers so fingers crossed they fit him well. I’m struggling to find anywhere that stock wide fit wellies?! Before I sized up and it was okay but I’d like to try and get him some that actually fit if anyone has any recommendations?! It’s bizarre to me that nowhere seems to stock them. Thanks in advance!