Your best possible option for dwarf food without making your own food:
https://www.rodipet.co.uk/pet-foods/...nior-500g.html
Burgess wouldn't be a great option as it is a pellet only diet which isn't suitable for hamsters due to lack of dietary enrichment(it does have potential use if ground up and moistened for ill hamsters or hamsters with no teeth though). It is also a better food than Harry Hamster, since there are only whole foods(no pellets) and no artificial dyes.