Yes, you can end early and there's an option to sell to highest bidder. But bear in mind, you may get more if you leave it running.
Here's the link:
http://offer.ebay.co.uk/ws/eBayISAPI.dll?EndingMyAuction
Or on My eBay click on the little arrow, far right of the item on your selling page > End Item. Or on seller hub go to the Active listings page, select the checkbox next to the item you want to end and from the dropdown menu select End item.
