Flour can sweat a little so airtight containers can be problematic. We used plastic wham boxes for flour and grain, as it appears the lids are snug enough to keep mice out but also not airtight to allow a little breathing.
Large batches (biggest bag is 16kg but there are over 20 of them at a time) are left in the bags but are stored in a vermin and moisture protected store. Enough for a couple of days is decanted into airtight containers for storage in the dough prep area.
Hey bakers, was there a consensus for the best option of storing bulk flour? What's the actual volume of 20kg flour?