Not for children. In fact, hamsters in general don't make good pets for children as they only wake up when the child is in bed, and depending on the age of the child they probably haven't got the manual dexterity and reaction times to handle them properly. I remember having a dwarf hamster as a young child. I don't remember handling it for that very reason.
Dwarf hamsters need just as much space as a larger, Syrian hamster, and if they are kept in pairs then they need more specialist housing to prevent fall outs that can lead to fatal fights - for instance, no levels or tubes to get territorial over, only hides with multiple exits etc. No, none of the cages that Pets at Home sell are big enough. You're talking about one of these, with the level taken out, at the minimum www.zooplus.co.uk/shop/small_pets/hutches_cages/hamster_cages/hamster_cages/284288 (or their Barney model would also be suitable). Syrian hamsters need lots of space, but have fewer specialist housing needs beyond size and a 28cm+ wheel - the Alaska, Barney or Alexander models from the same shop all work, and you can use the levels and tubes.
You also have to be very careful with the diet of anything sold as a dwarf hamster, other than a roborovski, as they are very prone to diabetes. We're talking zero sugar - not even carrots as they have to high a sugar content. Burgess Dwarf Hamster Harvest should be their main food.
Hamsters make great pets for adults who are at work all day, due to their nocturnal nature. However, for young children, I'd choose something that is a bit more robust from a handling point of view, and is awake during the day - guinea pigs are popular on MN, and rats may also fit the bill.
I'm happy to answer any questions about hamsters you may have - I have a Syrian, but have picked up a bit about dwarves along the way :)