Thanks Julie.
I think the other researcher chose the 1844 one simple because the reg had middle name Mill and it was Devon. Too many things rule that one out for 1861 marriage.
Even the death I have for Harriet (nee MOGG) although it fits for right parents on the reg, age at death is again about 10 years out, and does not fit with age on shipping record or census.
I'll wait for a relative to send me a copy of the tree that someone prepared some time ago and see how it fits with what I have found for MOGG, HANCOCK, MACKELLAR, BROWN, CLEAVE, PILKINGTON, WATSON, CLARK, DAVIDSON... the new branch of my tree.