Not having any success finding either in 1871.
FreeBMD has the deaths of a
Hannah Griffiths, Mar 1864, Tregaron, 11b 69
Thomas Griffiths, Mar 1871, Tregaron, 11b 59, age 58 (d.o.b 1813)
This Thomas' age at death, 58, doesn't quite tie in with his 1861 Census age/d.o.b of 42/1819
regards