Someone was asking about these recently.
At £2.49 a pair. Bargain.
At least *I think* they are selling D Cell - it's a bit hard to tell from the pic on their site - it just says 'various sizes'.
Strangely, my local Lidl [Yorks] was selling these last week. They were definitely full size D cells, not AA in a case. From memory they were 8000 mAh.