bunny mourning?

I'd be interested to know how some of your bunnies have coped with the loss of a companion and how it's affected their behaviour.

Since we lost Minstrel two weeks ago we decided to keep Cadbury inside so he didn't get lonelyon his own. He has been fine for the first week and if anything absolutely relishes the extra attention, follows us round the house, sits under the bed at night.

My hubby had to go away on a course for three nights and the night he got back Cadbury started marking different areas of the house. It really worried us at first as this was exactly how Minstrel's health problems first started, but over the past few days we have noticed Cadbury has marked the same spots at the same time of day. Even though he's neutered we're assuming he's just reasserting his position. He's used to being in the house and has never marked before, but he noticeably doesn't spend as much time in the hall and utility room (where we put litter tray, food bowl etc) as when we used to have both rabbits inside.

We're trialling putting his litter tray on the middle floor of the landing, but if anyone else can advise or offer any thoughts on bunny mourning it would be much appreciated