flanok,
Do you have the exact phrase your being found that this is happening on Yahoo? It appears that someone is just linking to you using the ww.shopbam.co.uk:
ww.shopbam.co.uk/?shopping
Maybe a affiliate or a coding error by yourself?
Either way just create a 301 redirect from ww.shopbam.co.uk to
www.shopbam.co.uk/ and problem will work itself out.