The main problems are
Reading a professional valuation may help to shed some light on
whether outbuildings etc. are occupied for agricultural purposes.
Derelict buildings are unlikely to have been occupied for the
purposes of agriculture.
If land is let on a grazing licence (
IHTM24073) and there are extensive farm
buildings, it may be that not all the buildings or structures were
occupied for agricultural purposes.
(This text has been withheld because of exemptions in the
Freedom of Information Act 2000)