Free bottle of Prosecco - Register for a C&B Party Organiser Privileges (POP) card at New Street Square in London
Just been over at the summer market at New Street Square in London and there's a booth for Corney & Barrow where they're giving out free drinks and also, a free bottle of Prosecco if you register for a Corney & Barrow POP card. Just show your card at your local Corney & Barrow to collect the bottle.
Very area specific and time-limited though since the market closes at about 4pm. But this may be a longer term deal that's available elsewhere since they're trying to promote their card.
Evidently, if you book a place at C&B with the card for a party, you'll get £1 per head to use for your party. Not a particularly cheap place to have drinks but you could save a bit if you already frequent that place.