Just raided my local Co-op (Darenth, Kent) - they have the best selection of BOGOFs there for a long while. Hopefully it's nationwide. Their prices aren't normally the best but on BOGOF they are pretty hot.
Muller snack size 8 pack corners (fruit and crunch) £2.99 BOGOF
Utterly Butterly 500g £1.45 BOGOF
Robinsons barley water 1 litre £1.35 BOGOF
Robinsons Fruit Shots 8 pack £2.79 BOGOF
There are many other items on offer too, so well worth a trip