Both are far too small, as others have said.
The Zooplus Alaska is suitable www.zooplus.co.uk/shop/small_pets/hutches_cages/hamster_cages/hamster_cages/284288 (84 x 48.5 x 44 cm (L x W x H); £32.99)
The Zooplus Barney is also a good option www.zooplus.co.uk/shop/small_pets/hutches_cages/hamster_cages/hamster_cages/189303?rrec=true (100 x 54 x 45 cm (L x W x H); £49.99)
Anything less and you are committing cruelty to animals. Just because a cage is made and sold, it doesn't mean it's suitable.
Also bear in mind that if you intend to keep a pair of dwarves, they can be prone to territorial fighting. They need no shelves, no tubes, and two of everything else (wheels, hides, etc.). Dwarf hybrids (aka Russian dwarves) are prone to a variety of health complaints, particularly diabetes and kidney failure.
Oh, and hamsters are not suitable pets for children, as they are nocturnal and only wake up when the kids are going to bed. Dwarves also have the added disadvantage that they're too fast to handle (even I, as an adult, struggle to safely handle my rescue dwarf because she's so fast - who came to me because her original child owner got bored of her)