Today only - use voucher code TEN.
Additionally, more savings can be had (thanks , scar!)
For those tempted to buy two one can potentially save an additional ~£1 when buying through Quidco and using the voucher code listed on the LoveFilm Retail listing:http://www.quidco.com/lovefilm-retail/?ac
This would (including quidco tracking of 5%) a total of £31.22 for £40 of credit compared to £32.25 when using the "TEN" voucher code - bear in mind this calculated value doesn't include Quidco tracking but I have excluded it as using a voucher code not listed on the Quidco site risks having the purchase not tracked/declined entirely.
For value sake if it Quidco did track (at 5%) alongside the "TEN" voucher the total would actually come up to £30.66, nearly £10 worth of free credit to use on the Playstation Store - up to you with which one to use.
As I don't use TopCashBack I cannot comment on the potential savings using them.
Hope this helps and happy gaming,
Original post - cheers for putting it alongside the OP silkhuk:http://www.hotukdeals.com/deals/psn-live-card-20-00-16-14-at-lovefi/788550?p=9705138
I have yet to try this myself so this is based on my calculations which may very well be incorrect, the final outcome of doing any of the methods below doesn't guarantee the quoted outcome - If I do purchase this myself I shall update this post accordingly.