I can't think of any animal in the uk that will remove and carry off the ear of a deer when other parts of the animal are readily available to eat first (though cats will chew ears) which points further to a road casualty, the ears could easily have been removed in a collision with a vehicle along with a portion of skin though. Regarding the visible injuries in photo, if shot by a poacher it would most likely be with a 22, it would be very difficult to see a 22 entry hole on a deer it would be so small, even with close examination it would be quite hard to find the hole. If a dog attack there would be lots of deer hair spread all around the area, and dog footprints in the mud, fallow deer put up a terrific struggle against dogs and the signs would have been quite evident, to kill they would have to have had a throat hold and its common to find puncture wounds in the throat area on the underside of the neck, the wounds in pic seem to be on the top of the neck/head which is an unusual place for dog bites to be. Typically dogs do a lot of damage particularly to the deers hind quarters and to the underside of neck and you would most likely have found chewed hind quarters and neck if a dog attack. That wound on its hind quarters doesn't look like a bullet hole but if it is it would mean its a larger calibre than the poachers weapon of choice, a 22, so it would most likely be someone with permission or a farmer, if it was a stalker it was an incredibly poor shot, only heart or necks shots are taken, it doesn't look like a bullet wound to me though. Yes they are heavy to move, does are usually somewhere 70-100 pounds but can be bigger.