CG64680 - Private residence relief: non residential use: part of house used for business: farmhouse
Whether any part of a farmhouse is used exclusively for business purposes is a question of fact. In what is probably the normal case, parts of the house, for example, the farm kitchen and dining room are used for business but are also used domestically. So each of these rooms should be treated as part of the residence regardless of the fact that the farmer receives an allowance for his or her business use of the premises in the computation of the trading profits.
If there is exclusive use, for example, of an office or dairy, then an apportionment is necessary, and the relief should be regarded as extending only to that part of the farmhouse which was occupied partly or wholly as a residence. The computation should follow CG64663.