Thank you Nick, just had a quick read through and although it gives some facts about what are pest species and which pests, birds and mammals can legally be shot with an airgun (under the general license rules), it does not list all pest species that can be shot with a sub 12 airgun. Just because they are not on their list, it doesn't make it illegal to shoot mice for instance.
There are various figures touted for the foot poundage needed to cleanly kill a rabbit with a well placed head shot, but I have never seen any figures given for Hares (which must be more).
Finally, I was offered to shoot as a guest on a couple of farms that were over run with hares, but there is something strange in my brain that says rabbits, yes, hares NO! Similarly, I dislike magpies intensely, but love to see doves, one mans meat.........