The Oxfam shop I work in tell people they need 2 referees but only very rarely contact them. So the references you have don't need to be employers or anything they can just be a teacher or family friend. Hope you find something, I find volunteering in a shop really rewarding
I volunteer in a Sue Ryder shop - which I'd really recommend by the way, it's a lovely place to work - I had to provide 2 references, I just did my form tutor and my piano teacher, and my piano teacher didn't even know I had put her on there! It's highly unlikely that they'll contact them. There are always charity shops that need volunteers because there are always things that need doing so have fun - I really enjoy it