For an overview of the taxation of ministers of religion see
This page gives an overview of employment expenses that ministers can deduct.
Ministers have their own special legislation dealing with deductions for expenses in Section 351 ITEPA 2003. Part of that is very similar in wording to Section 336 ITEPA 2003. So the guidance on what is allowable under Section 336 should be used in deciding if a deduction is allowable, see EIM31620 onwards.
Section 351 allows some additional deductions beyond Section 336. For details of what that means in practice see EIM60044 onwards.