Like Starry said, the boo is only a fitted, so needs a waterproof cover over it.

But it still should take longer than an hour to leak through. Did you have both boosters in it? Also, did you strip wash them when you received them? it may have a fair bit of residue on the fibres, which basically clogs it up and makes it less absorbant.

Try a hot wash with a few drops of tea tree and dishwashing liquid, and an extra rinse, and see if it makes a difference.

Does it fit right? It will seem to leak through if you have leg gape or tummy gape where the wee can leak out without actually soaking THROUGH the whole nappy, so check the fit too

HTH