Leaving his mark

Hello Think Tank,

I have a rescued an eight-year-old male Bichon Frise and I have had him for three years. When I first got him he was unneutered so I had him neutered fairly quickly.  He is very loving and a very good boy at home because he is very cuddly and doesn't wet in the house.

For three years he has been looked after at a dog sitters house where there are up to four other small dogs. He loves it there and is content.

But recently he has been lifting his leg and 'marker' weeing in certain places. Also he has been pestering a male dog for a lot of time during the day! He has never been bothered or interested in other dogs - until now!

I have tried using 'scullcap and valerian' tablets but they do not seem to work.

Can anyone help me to find a solution to this new behaviour please?

Thank you. 

Regards,

Terri Sherlock