Does anyone in UK know where to buy wool rovings or cotton tops for needle felting/embellishing crafts ?

Feltmakers, spinners and weavers may have the answer to my question. The problem is I don't know anyone in these fields. I am knowledgable about many aspects of textiles but this is a new area for me.Can anyone help? I would be happy to hear from people who are involved in this craft I live in the U.K.