Posted: 17/03/2015 at 13:41
Jake Ansell. You say "it's black, smells of nothing and is full of brandling worms."
Lucky you. What you have is worm compost and it should be mixed 40% to 60% soil for best results. Soil, leaf mould or peat would be good. multi purpose compost would be my last option.
You will have great beds.
Here is my thread on vermicomposting. If you would like to venture down that route.