Griffiths Mill - I've been here and seen the operation. Karen is a spinner herself, and takes great care (and pride) in setting up the equipment just
so for the fleece she is processing at the time. If you have more fleece than you need batts, rovings or yarn for yourself, she may be prepared to market some of it through their shop - it's worth discussing with her.
The Natural Fibre Company. Have a minimum quantity of 20kgs incoming
per breed/type, but do have a 'matchmaking' service where they can put two similar batches together. Output quality seems to be very good indeed, from all those I have seen and heard of.
Halifax Spinning Mill. Many happy customers, but I do hear the occasional grumble.