Sorry, folks - I've looked at the ts and cs and agented people are out, because the winner must agree to be represented by Furniss Lawton agency.
http://richardandjudy.whsmith.co.uk/search-for-a-bestseller-form/#s4abstscs
Not only that, but it says you must:
'have not previously submitted your partial novel (the “Extract”) or any work to a publishing company or literary agency and have not been previously published in any format, or released into the public domain, including but not limited to the Internet;
AND:
'have not had any other work published in any format whether under the entrant’s name or a pseudonym;'
Blimey. Suppose they're just making sure JK doesn't sneak in under the wire...