Probably just ordinary Chinese Zinc Carbon presumably licensing the brand. I've been buying packets of 14 for €1.49 from Dealz (curiously labelled as 12 + 2 free), which is the Irish subsidiary of Poundland. Regular HT packs use 60 and the B137 uses 120
They recently stopped selling them and have a lot of over priced "Simply Duracell". They also though have Sony (branded) PP3 Layer cells, Kodak (branded) Alkaline PP3 (I don't buy them for battery packs as they are too fat), Polariod and the "Ford" branded batteries since the JCB batteries ended.
I seriously doubt Kodak make any batteries or Sony make those Zinc Layer cells. Sony unlike Ford, JCB, Polariod, Grundig and Kodak do make some kinds of batteries. Curiously my no-name Chinese made bought from USA reseller replacement Lithium pack I got just last week appears to have Sony batteries. At least it tells the lap top that they are Sony. Most of the Lithium packs I've opened have actually been Sony.
I have used Kodak Alkaline D and AA and also Kodak Zinc Chloride AA (a marginal improvement on Zinc Carbon at 10mA HT). Ever Ready "HP" were Zinc Chloride.
I weigh batteries and this tells me what taking apart confirms. ALL the Zinc Carbon I have dismembered, no matter brand have much less battery than in the 1970s. They use a fat hollow plastic bung to seal rod & case top instead of card disc and thin layer of tar. But they have taken to putting TWO of them!
Same on AA cells.The Alkaline are still filled
Top is Alkaline (case is positive!) the cap is the negative base
Bottom is Zinc carbon with the two bungs and positive carbon rod to top cap removed (case negative)
The metal work in older sets is usually negative. The Alkaline cells have a very thin easily pierced shrunk on plastic film and thus short.
Actually even the Zinc Carbon have poor case insulation. Accidental shorts to torch bodies or each other is so much easier today.
AA bungs ...