I was having a look again and it's a little confusing in places, but I think it's the paper flake bedding that is intended for hamsters. Those larger packs say for guinea pigs, rabbits, chinchillas and hedgehogs.
And my maths needs looking at too as 1.2kg is obviously larger than .85kg

I read it as 85kg, not .85kg. So neither is a very large pack for the price. Hard thinking in kg as well when everything else is in litrees.
But as a comparison, Fitch used to be in 10kg (large) and 20kg (huge) bags, before it changed to litres. The biggest one now is 70 litres which was supposed to be the equivalent to the old 10kg bag (but is slightly less than before in my view).
So if the paper flake is 1.2kg a bag and there are 12 bags of it, then it's about 14.4kg - so technically those 12 bags should be more than a 70 litre bag of fitch. But when I've bought fitch in smaller bags, I found the equivalent number of small bags didn't seem to give as much bedding as one large bag! Which I always found confusing (but their small bags were compressed).
And yes the other type is recycled newspaper, which personally I wouldn't want to use. I don't see how it can be allergy free if it is recycled printed newsaper (unless newspapers have started using non toxic, allergy free inks). I do remember someone saying a few years back that newspapers no longer used toxic inks but ......... AI says although newspaper ink is less toxic than before, it is still risky if ingested. Which would be my worry (mind you AI isn't that reliable!).
The recycled newspaper bedding they say is for nesting and burrowing and is in the smaller packs, so I think just the paper flake bedding would be the only one suitable really. Their shop only seems to sell packs of both,
So I've had a look at their list of stockists. One of whom is Jollyes, who sell the paper flake bedding from NIDP. Where it says it's white, soft and dust-free, hypoallergenic and won't cause harm if the pet eats it. They sell it 100g bags for £1.26. One kg is 1000 grammes, So 10 bags of 100g paper flake would only give 1kg of bedding. 10kg (the equivalent of a large bag of fitch) would be 10,000 grammes. So you'd need 100 bags of the 100g paper flake bedding to give as much as a large bag of Fitch. Which would cost £126!
The descriptions are confusing. It's clearly sold in small, nesting sized bags but marketed as litter/bedding for hamsters, mice, rabbits and guinea pigs.
Jollyes also sell the recycled paper bedding .85 kg (so an even smaller bag also at £1.26) made from recycled newspaper which they say is chemical free and won't harm skin or fur, and intended as a "base" bedding. And they say it smells like freshly baked bread
It also says you don't have to worry about accidentally poisoning your pet with that product. Which is also confusing if it's made with recycled newspaper.
Best pets sell the paper flake bedding (not recycled newspaper) in larger, 5.8 litre compressed bags (which they say is the equivalent of 0.9kg). Those are £4,85 a bag. So 10 of those would be £48.50 for 9kg (maybe the equivalent of a large bag of fitch or slightly less but costs more).
But - they (Best pets) also sell a large 10kg bale of "paper strips" bedding for £25.89. Which is cheaper than Fitch. This sounds like the equivalent of the fitch paper strips bedding, which people have found isn't good for hamsters as it gets tangled. The normal 70 litre bag of fitch is the pieces rather than the long strips.
I looked at a few other stockists as well who mainly sell the smaller bags. It's all a bit confusing, but I think it isn't really an option personally.
The recycled newspaper can be ruled out IMO due to potential risks and the fact it's only sold in very small bags,
The paper flake bedding would be too expensive as only sold in small bags.
The paper strips bedding is sold in larger bales of just under 1kg but paper strips aren't great for main bedding I think.
Although that could be worth trying as it does work out cheaper than fitch if you buy 10 of those.
I just remember when people have accidentally bought the paper strip fitch instead of the pieces, it didn't work well.
It's annoying really as it would be nice to support a supplier like that - but I can only assume it's not cost effective for them to produce bulk quantities of the paper flake bedding. Either that or they don't realise people buy bulk bedding for hamsters (the bulk strip bedding says its for dogs).