I use pampers baby dry nappy pants and never had a leak at night. They do a size 4+ too which is a side 4 but even more absorbent which I use at night now x
Try sainsburys size 5 or pullup! Remember we had same issue but wee leak not poo
I use Aldi nappies during the day but found my little one was always leaking at night so I now use pamper premium protection at night and never had an issue since