Perhaps I could add a more technical answer to Swancott's sensible comments. A parish council may only spend money on matters for which it has a power in legislation. There are many powers, but the description "whatever church requires" is too vague to fall under any specific power.
The remaining power is the Local Government Act 1972 section 137 (often referred to simply as section 137). This allows a parish to make a grant that is not covered by any specific power, provided there is a direct benefit for part or all of the parish that is commensurate with the cost.
To satisfy this criterion, it would seem that the council would need to know at least a little more than "whatever church requires" to be able to lawfully make a grant, or would need to make some effort to spell out the benefit expected to accrue to the parish.