The answer is easy. You take the aforementioned 50p to a bank. You have to write a cheque within 'a' radius to the Government.
They naturally will ask the seven sided questions:
Where did you get it?
Did you charge VAT on it?
Are you VAT registered?
Have you declared it?
Is it a gift?
Are you a British citizen?
Are you a teacher with time on his hands?
Therefore, the answer is Vodka and Lemonade times loads = don't understand the question