Having dug deeper, Amelia Morgan/Luff didn't marry a Hulin, as both Amelia Luff and Amelia Hulin are on the 1841 census. In 1841 your Amelia was a servant in the household of William Peel. There's another Hulin working as a servant in the household, looks like Norah, age 14. Presumably your Amelia had a dalliance with one of the St Briavels Luffs, whereas Amelia Morgan married a Llandogo Luff.

Oh, well, back to the drawing board. :-)

-Jean.