I have a client that has filled in IS form himself, His situation is quite complex. The client seprated from his wife in 2004 and currently still has ongoing divorce settlement issues. He lives in what was the family home. For the past 3 yrs he had another partner on and off at one point she was living with him part time but this has now ended but the couple are still together, partner had to move out because of the clients drink problems. He is applying for the reduced rate of IS during the appeal period. She does not have any involvement in the running of the home etc,

My question is should the girlfriends details go on the form and will this affect his claim to benefit/

Are they living as members of the same household? Does she have another address which is where she actually lives? If you/he can put your/his hand on you/his heart and say "no" to first and "yes" to second then they are not living as a couple.