Stuck with a bin

[Footface]

I changed to listing to bin, he bid on it, but its still sitting in selling section rather than sold, did I do it wrong

Do you have to end item maybe?

if the buyer bid on it then presumably that wiped out the buy it now price?

You can have an item listed as both BIN or Auction, but unless you have a reserve of £50 or more then any auction bids will end the buy it now option.
That is why your item is still in your selling section, it remains open to bids from other people.