Just popped in to my local co-op (Wilsden) and they had these by the self service. Bought the cranberry ones before - Think they were about 80p. Scanned through at 25p. Got 4 boxes for a £1 in the end. This is the eucalyptus flavour, not sure if all flavours are the same price.
I thought these were relatively new but possibly already being delisted hence the reduced cost.
No receipt as the machine didn't give me one!