Thames River Cruise/Lunch x 2 ?

I have two tickets for a Thames River Cruise for two people which I can no longer use (all Saturdays cruises are now booked up until October). Details are as follows: Date: Saturday 18th August Elite Lunch Cruise Pax: x 2 Vessel: Naticia/Harmony Schedule: 11.45 Guests start to board at Embankment Pier 12.15 Depart 13.45 Return to Embankment to disembark Please be advised that once the boat departs, it cannot return to the Pier to collect passengers, so please make sure you arrive in plenty of time to avoid disappointment. Refunds will not be offered in such circumstances. - Guaranteed Window Table - 3 Course Set Lunch Menu - Coffee or Tea - Half a bottle of House Wine & Mineral Water They cost £43 each but would sell at £40 each instead. More information can be found at http://www.thamesdinnercruise.co.uk/lunch.htm