If you have less than 5Ha and the land is outside of the residential curtilage then any structure, hard standign or engineering operation should require planning permission. My dad has 3.5Ha and lives on site but still required planning permission for a polytunnel and a hen house.
If you are reaign it from this website https://www.gov.uk/planning-permissions-for-farms/when-you-dont-need-it then the term "farming operations" does not refer to the construction of bulidings, it is (in my reading of it) saying you don't need permission to plough, pile muck, errect fences etc.
Okay, so let’s say I have a land that’s over 5 hectares.
Based on the ‘permitted Development rights’ I can erect an agricultural building without planning permission.
Am I also allowed to reside in a temporary accommodation on the same land to run my business and look after my live stock? Does this require a planning permission?