I am so glad other people are interested!
So I used a plastic storage tote/bin, I think you could get them at Asda, or any sort of store like that. Here in the US we have them at Wal-Mart, Target, Home Depot, etc. I am using a medium sized one, but you can really go with any size, depending on how much you want to use it. I just cut some large holes in the top and I keep the lid on.
I used coconut fiber as my substrate, which you can buy from any pet store (Pets at Home UK< Petsmart US). I bought condensed bricks of it, in the reptile/amphibian section, and filled it about halfway with substrate.
I bought regular old earthworms from the pet store, and red wigglers from an online distributor. I put all of the poop in, all of the leftover veggies, and SOME of the hay. I do not use all of the hay, because it is best to keep the substrate moist (coconut fiber hold its moisture, I use it for my crested geckos as well), and the hay gets moldy pretty quickly.
Some things I have learned along the way: FRUIT FLIES. There are a lot of them. They pretty much stay in the bin, and I have recently bought a piece of burlap to lay on top of the substrate to hopefully keep the flies down, as well as the worms warm (they like to be warm). I also use a red wine vinegar and sugar solution in a cup with plastic wrap and holes over it to trap them. I also recently bought some worm food, because I have a lot of worms and only two pigs. I am hoping this will keep my worm production up.
So far, the pig poop composts really well this way, and I am definitely going to continue the project. They're obviously very low maintenance, and I have them tucked away under a table, so I often forget about them for days at a time, and it does not matter at all. You could also compost food scraps, paper, etc, but this will make the fruit fly problem a bit worse.
