From Amazon
Varta 42332 LR14/C (Baby) (4114) - alkaline manganese battery 1.5 V x 2
The product is available from £2.52 at international stores.
Conrad Electronic
Varta LONGLIFE C Bli 2 C battery Alkali-manganese 7600 mAh 1.5 V 2 pc(s)
OnBuy
Varta Longlife Extra 1.5 V C Alkaline Battery (Pack of 2)