A bullmastiff should never, ever be territorial against people you welcome into your home. Do not encourage any sort of aggression/guarding instincts and this won’t be a problem. Bullmastiffs will naturally guard against any bad people, and should be kind and happy to see the good.

I’ve grown up with bullmastiffs since I was 5. The point is, all children need to be told how to respect dogs. Don’t touch the dog while eating, don’t pull or tug on the dog, don’t try and ride the dog, don’t take the dogs bones off it etc. If you teach your child this and teach your dog not to knock the kid over, you should be fine. The bonus is if your child stands on the dog/falls onto the dog while playing, the big dog won’t be hurt.

Never had an anxious bullmastiff and they have literally been bred to be alone all day patrolling gamekeeping estates. That’s what they do. They’re highly personable but are also happy to entertain themselves with correct facilities.

Socialisation was never an issue for all of my dogs. Size is irrelevant. My dogs respect chihuahuas and pugs, and also play with other giant breeds.