Phrases such as this may have different meanings according to where and how they are used. The JPAG definition is "Net revenue expenditure is defined as precept, less amounts included in precept for loan repayment, capital projects & transfers to reserves." This may not be appropriate for parish councils, particularly the smaller councils that tend to live a more hand-to-mouth existence.
Many smaller charities describe their reserves policy in simpler terms such as 12 months operating costs or 12 months recurring expenditure. This may provide a more meaningful measure.