My friend has a lovely rescue Patterdale mix (mostly patterdale). He is soft as grease with people and children but he does show a lot of aggression towards other dogs. My friends are working on his issues but they are struggling to find insurance that will accept him. He is walked with a muzzle at all times and isn't allowed off lead. Any recommendations on Companies? I've suggested public liability as a basic requirement and then to go from there.Thank you.