Night Nappy help!

I'm having issues with DS's night nappies and would like to be able to do away with using disposables if possible (although they are so convenient ATM) I usually use Peapods pockets stuffed with 2x cloth flats which are absorbant enough but too bulky to I'm having to change pj's and sheets daily cause the poo is leaking out I fold the flats into thirds along one way, and then in half the other way, then into thirds again along the same way if that makes sense!? I'm not sure if there is another way to fold them that might work better?
Or are there any suggestions of other nappies that might work better, I can't afford to spend much at all on new nappies either.

The first thing I'd suggest is to invest in some proper inserts that will be more absorbant with less bulk. Even the cotton prefolds might be better than the old flats. Better inserts might work well at night in your peapods (although peapods always leaked with my daughter so I gave up on them early) and lots of people sell inerts and boosters on Trademe or you can try Ecomoon, Snazzipants or heaps of other sites. Just remember you want to team up a fast absorber (microfibre or cotton) with a good holder of liquid (hemp or bamboo).

The next cheapish but excellent option would be to team up a bummi's super brite cover (double gusset to keep the poo in) with tons of stuffing (I use a cotton prefold with lots of hemp underneath). This works really well and I've never had a leak of any sort with this system. I'm sure there are other covers that would work as well but this is the only one we've had. Other people talk about Pop in dream dry nappies but I haven't tried them yet. Ecobubs are expensive and have worked brilliantly for me but other friends have had nothing but problems with them.

I've never got on with pockets for nighttime... we have bamboo fleece fitted cloth nappies with separate cover for nights. They are a pocket style so you can boost if needed. You might be able to find something similar on line - secondhand bamboozles turn up on trademe occasionally? They aren't a pocket, but do have a flap that you can tuck other stuff inside.

We use bamboozles at night, with a seperate cover. For both my toddler and baby.
No leaks at all, and pretty trim fitting.
I haven't found any pocket nappies that work at night without leaking.