dvdgremlin
There is a third requirement that you are living alone or considered to be living alone, is this the case?
If it is then you should contact the DWP office dealing with your ESA claim and ask for an IS10 form or to complete one while you are on the phone, it's a simple form that ask about your PIP award, about anybody that lives with you and what benefits they receive if any.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems