hi we bought our first boat from sawley marina, central and very helpful... although thier website is rubbish and terrible pictures of boats. what about the new and used boat company they have a few places across the midlands, great website and nice selection of boats.
however, if you're not getting bites from appollo i think you need to think about the pictures, price and how you're marketing it. this was last year but we sold ours on within a month on that site, price was the main factor - get it right and it should sell quickly... get it wrong and it will sit there for months.
good luck