Members of a Parochial Church Council are also charity trustees, as all PCCs are charities.
The Parish Resources website has helpful material on PCC members and what it means being a trustee.
The Charity Commission produce a range of publications to help trustees:
There is a Trustee Eligibility Declaration for use by members of PCCs (updated January 2019). (Please note that this is a word document which requires the PCC to insert their own Charity name and registration number and a link to their Privacy Notice prior to its completion).
There is further information about PCC charitable status, and also about the circumstances which trigger mandatory registration with the Charity Commission here.