Customer in front of me purchased this and the till assistant told him to go back and get another as they were buy one get one free! So I went and picked up a couple of pairs and everyone around me that heard went to go do the same so there wasn't many left in the Folkestone branch when I left.
They were right at the back of a fridge with no signage indicating the bogof offer...till assistant didn't know how long the offer is on for but said that the offer is across lots of stores. The expiry date on the ones I picked up say 20 Feb 2015.
You can freeze this cheese but in my experience it becomes a bit crumbly afterwards but still fine for melting cooking etc.
EDIT: Apparently BOGOF is now finished :( But worth checking your stores for fresh deliveries of this cheese for 99p which is still a brilliant deal!
18/12/2014 My local store today had plenty out on display about 5 large boxes full so it looks like it's being restocked at the 99p price.