I have a nearly one year old BT who has just started marking in the house. He is definitely marking as opposed to having accidents. In the last couple of weeks he has discovered leg cocking and he has now stated marking three different places in the house as soon as my back is turned. There has been no upheaval or change in the house, nothing is different. He is being castrated in a couple of weeks as he has a medical issue that requires it. Any advice?