I've just been to visit a wonderful new Mini Mill near Sudbury in the south of the Derbyshire Dales. It's actually just off the A50 near the Ashbourne turn off (A515) and a stones throw from the Museum of Childhood.
Karen and Dave Griffiths set it up in April after several months of training in Wales and what's so great it they have very small minimums. Actually as little as a fleece! So if you've got a great fleece that you don't have time to prepare then Karen is your man! In practice, it's obviously worth getting much more processed, but Karen is keen to provide a service for anyone that she will process just one fleece. Take a look at there prices, by following the link above, which I think are very reasonable indeed.