My baby is exactly the same overnight, we just changed to pampers size 4 pants and problem solved! We use normal Sainsbury's nappies in the day as changed regularly and no issues but overnight we found the pants do the job :)
We've just switched to pull ups and they've been a game changer. Haven't had a single leak with them so far.
We put two nappies in our LB overnight since he started leaking and it’s worked a treat! We put a pampers on the bottom as they hold more and are more comfortable then a cheaper supermarket brand (we use Sainsburys) on top!
I had this problem with my little girl. We moved her up to the next size up nappies for night time and it’s worked amazing! X
My little girl never sleeps through as I still have to feed her 2-3 times a night but we have had the same issue with leaking which we never had before solids! We sized up with the Aldi nappies and that helped a tiny bit but I’m having to change her at around 2.30 every morning otherwise it means having to change her sheets every day!