St Mary's church, Witnesham is managed by the Parochial Church Council (PCC).
PCCs are charities but are ‘excepted’ by statute from charity registration with the Charity Commission of England and Wales by statute if their income is £100,000 p.a. or less, but they're still subject to that bodies’ regulation (see the Charity Commission’s guidance titled ‘Excepted Charities’).
In plain English, this means PCCs with an income of less than £100,000 are unlikely to have a Registered Charity Number.
And this is the situation with Witnesham PCC. It's not registered with the Charity Commission and hasn't got a charity registration number, but is a charity for the purposes of the Charities Act 2011, and registered in the diocese of St Edmundsbury & Ipswich with code 633030.
The authentication certificate for proof of charitable status can be downloaded below.