From an e-mail dated 6.10.08 (after the starting date of the promotion : 'We’re pleased to let you know that from 1 October until 31 December 2008 you’ll earn 50% more miles when you spend £300* or more each month on your Virgin Atlantic American Express® Credit Card from MBNA.

and

'All you need to do is spend more than £300 in any of the three months during the offer period and you’ll automatically receive 50% more miles than you normally would each month.'

From the T+Cs:

'*When you spend £300 or more per month on your Virgin Atlantic Credit Card from 1 October 2008 to 31 December 2008, 50% extra miles will be displayed on your monthly credit card statement and allocated to your account within 30 days of your statement date.'