Abandonment.

Possession - Section 8 and Section 21

Hi I was wondering if anyone could shed any light on this situation..

Currently got a tenant who has been served a section 8 (which expires today) and a section 21 (which expires 07/08/2013) It's a joint AST after the fixed term, one of the tenants has handed the keys back and surrendered the tenancy. The other was still living in the property. The guy that is still there was an alcoholic who has a history of self harm (I'm not sure if that is relevant but just wanted to give all the info.)

Last week the tenant that had moved out (the guys ex partner) informed me that the guy has moved out and is living elsewhere. He has never brought me the keys back, nor has he signed a deed of surrender he has simply just gone. I have checked with the neighbors and they confirm they haven't seen him entering or leaving the property for some time. I can see through the windows that there are still personal belongings in there. But things that I know were of Value or sentiment to him have gone.

Also, the front door to the property is open with 2 chairs blocking the doorway so effectively no one can get in but the door is unlocked.

I have tried to contact him numerous times on his mobile, I've hand delivered letters asking him to get in touch. I have called his place of work and left numerous messages asking him to contact me.

Can I now put a notice of abandonment on the door? Sorry for the lengthy post I just wanted to paint the whole picture.

Many thanks.