I volunteer for a local charity, and we have a new volunteer who is becoming a slight problem. She is a lovely person, very committed etc, but she is acting as if we are close friends and and as if the charity is the centre of our lives. For example, she will call for a chat about the volunteering and expect to chat for an hour or so, whatever or wherever I am. Frankly, I'm not that interested, I have other friends I am closer to that I would rather chat to, and I have a life to get on with. This is more than just saying 'I can't chat now' - I need her to back off - but I don't want to leave the charity. Help!