Hi guys.. we have a 2 year old Portuguese water dog bitch. She is exercised several times a day and is fairly well trained. Weve had no flummoxing issues with her until about 3 weeks ago.... we live in a small rural village and during the school run, she has always been left tied up outside the gate while we go into the playground. (We can see her at all times)this has been the case for a year and a half and there has never been as issue. Randomly, three weeks ago she started barking about 2 minutes after we left her. My partner went back to check she was ok as she never barks! But now it's constant... she's quiet for about the first minute or so and then she barks until we go back out. What is the best way to go about resolving this? She's very rarely left on her own but did do an overnight trial session in a kennels shortly before this started....could it be the cause?