Hi,
As far as I know in England, as long as you have a licence for your gun you can shoot deer at any time (but I'd double check)
Deers do destroy trees, even well established ones can be severly damaged by the bark being eaten off.
The only suggestion I can come up with is to put deer fencing around your orchard and/or garden to prevent them getting in (think of the stuff they use on deer farms or possibly builders panels) but this may not be practical. They may keep their distance once you move in - especially if you have dogs, but they may not !
I'd go with the gun & big freezer option myself - venison is lovely ! mmmmmm
Karen