Hi Stoatytoat
We have had quite a few into our rescue centre and if they are young ones they are sent to Stapley in Cheshire where they do a release program.
They tag them and release them in small groups.
We also have had them in our roof!! We live in a forest on the Herefordshire/Shropshire border and when we first moved in I checked the attic for bats (sad I know but we do have them in our wood shed!) anyway, I found Polecat droppings up there, and I found a dead adult Male Polecat at the bottom of our lane. They do grow to a huge size, at first sight it looked like a dead badger cub in the road!
A few years ago we also had some babies in from Shrewsbury library too, so they are around and we had about 4 in last year!
cheers
Jo