I've been unsuccessful searching for census records or a death record for the Rev John Jones below.

"MARRIAGES. On the 4th inst. (4th December 1866), at Pencarreg Church, Carmarthenshire, by the Rev Thomas Jones, vicar of the parish, Richard Thomas, Esq, only surviving son of the late Rev W. W. Thomas, B.D., rector of Dinas, Pembrokeshire, and nephew of J. H. Thomas, Esq, surgeon and accoucheur, of Llanfechan, Cardiganshire, to. Catherine Henrietta Jones, youngest daughter of the late Rev John Jones, Vicar of Llansaintffraid, Montgomeryshire."
- from Potter's Electric News 12th December 1866

Also - "On the 7th inst. at 36, Cambridge-street, Pimlico, aged 26, T. H. Jones, Esq, eldest son of the late Rev. John Jones, vicar of Llansaintffraidaid, Montgomeryshire." - from the Wrexham Register on 16th May 1857.
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Any help will be much appreciated.
Richard