Thanks everyone, just the kind of hands (or boots) on experience we wanted to hear about. We've got a few Scottish expeditions planned this year so we will now try to visit "deserted farm" sites and may even try some Bold Farmyard Parking (with dash note, phone no. and complimentary fruit basket).
We will however be asking for donations if our car gets forklifted into the slurry tank by an irate farmer.
Maggie & Keith