The council minimums are found here:-
https://hamsters-uk.org/content/view/29/48/
Keeping in mind that this is the absolute minimum that a hamster can live in and is backed by appropriate research. It covers every hamster from breeders to pets. When I rehome I advise an 'ideal' cage size for a syrian be no smaller than 60cm long purely because that encompasses the biggest range of choice and prices. Most owners go for 80cm although that's harder now the Barney cage was made into 100cm. Most don't ever go that big because it's not feasible.
I think as it depends on the hamster so much that a minimum cage guidelines shouldn't be too big as Cypher said.