Capital allowances for self employed - property

Lippizanna

Could someone help me please as I have never dealt with this before. I have a client who is self employed. The information she has given me is a little vague but I understand that earlier this year she bought a bungalow with her husband and father in law. Part of the property is let out for residential and the other part has been converted for her to use for her business. Can she claim capital allowance for her portion of the property and what records of proof do I need that she owns that part of the property ? If it's proven that she has no ownership (i.e owned by husband and father in law) presumably she can't offset. Any advice would be appreciated