PlayStation Plus: 12 Month Membership £37.49 @ Amazon, Game, Smyths
25% off for a limited time (likely ending March 26th).
Also available on the PlayStation Store for lapsed/non-active subscribers. Buy some discounted PSN Credit via CD Keys for the best value (.e.g £35 credit is £29.99 on CD Keys).
* Please note that all prices are correct at the time of posting. However prices can vary quickly and significantly without warning.