Instructions:I posted this before and it wasn't working, but it now is.
This deal was on before once as well, but you can now claim another voucher.
I believe that the voucher gives £1 off everything, no minimum spend.
If you have not registered for the site, do that first at PESfan.com (remember to confirm registration via email link)
Then log in, click the link in this thread then select 'click to claim' and you get your voucher displayed on screen and sent to your email address.