Hi! I see you posted this two years ago... I hope this is still helpful.
I've been looking for a harmonica and found one for £4.50. I don't think it has any buttons. It was from a little shop in York, 'Blossom and Walker'. It says 'Ridley's' on the box it came in and there is a web address for 'Wild and Wolf' but I think they're a trade only website.