Contrary to what some people might believe, local churches are largely funded by one-off and regular gifts from church members or other organisations or individuals.
Historic churches are particularly vulnerable to funding shortages since heritage repairs are often very expensive to ensure work is carried out to permitted standards and because the skills required are usually quite rare.
For church members, the best way to give is by gifting a regular fixed amount with the tax recovered from HMRC if you are a UK tax payer. This can either by done via an organisation like the Diocesan Parish Giving Scheme or Stewardship or can be claimed back directly by the PCC with Gift Aid. Gift aid requires the signing of regular statements to the effect that you are a tax payer and also requires the PCC to process Gift Aid recovery from HMRC so giving schemes are preferred.
If you wish to make a one-off donation, leave a legacy or specify where you want a gift to be allocated, please talk to a member of the PCC for the parish that you wish to donate to, who will advise on the best course of action. If you are making large donations, you should consult with an Accountant who can advise on making your gift the most tax efficient.