The relevant part of section 10 of the 1940 finance act which refers to an exemption for farmers.....
"the provisions of this Regulation shall not apply in the case of any person in respect of whom the Commissioners are satisfied that his main source of livelihood is the cultivation of land for his own profit and that he does not regularly carry on business as a seller of cider"
.....was repealed and removed by section 83 and the first schedule of the finance act 2003, so has not been in existence since then.
Mark.