Research continues to find Harriet. Noted Harriet can be spelt Harriett, Harriot

Baptisms – there were 2 other Harriets baptised near our Harriets baptism as follows:

1812 Truro, St Mary  Harriet daughter of John & Ann Sampson – 1881 English census lists Harriet Sampson 69 unmarried born Truro
1813 St Hilary Harriet daughter of John & Grace Sampson (our Harriet)
1818 Paul  Harriet daughter of Henry & Sarah Sampson

Burials
9 June 1856 Phillack  Harriet Sampson Age 45  Residence Angarrack (Could this be her?)

Marriages
19 Oct 1846 Parish of Stoke Climsland
John Hampton miner  and Harriett Sampson servant . Father of bride Joseph Sampson.
Ages of bride and groom not stated. Instead given as full age.
Note: A Hariet Sampson was baptised 5 July 1828 at St Agnes to parents Joseph & Jennifer Sampson

1841 English Census
Middlesex St Pancreas Mary??bone, Frederick Place,  Harriet Sampson 30 Not of this county. (Could this be her?)

It seems likely from the above that Harriet has moved out of Cornwall.