I got a special purchase "fleece" blanket from John Lewis for £10. I've made 24 liners from one side of it (the other side is a bit funny). I looks like it is this one http://www.johnlewis.com/230731764/Product.aspx
ETA that this is minkee even though they've called it fleece.
Cloth Nappy Tree gives you a free, unbiased and privacy rich place to discuss and recycle your cloth nappies. Save time, money and our planet by inspiring and helping others.