If you leave by 8.30 am on a Saturday or Sunday you can drive whichever way you want to Surrey (A24, A3). Leave it any later and it takes twice as long.
Why not just electrify the whole roof if it's copper, then the miscreants will be dealt with on a permanent basis. Otherwise surround it with razor wire- or is it illegal- because the poor little thieves might hurt themselves?
The postman and delivery drivers always knock and ask us to take in parcels for next door. They also put a card through their door to say that their parcel is with us and the neighbours come and collect it. You just have to engineer the situation.