When I looked up the deaths, I got a james wannan died in Dundee in 1830 aged 64, and his job was a weaver. and I've just noticed on the death certificate of his son James Wannan who was married to Agnes Ritchie, the father's job is noted as being a weaver, I am learning to be a lot more attentive to the detail on these papers than before, do you think that could confirm that it is the same James.
on the original birth lists for wannan, there was a James Wannan born to James Wannan and Elizabeth Donne in 1766 in Kettins, which is somewhere in Perthshire.
I've just read your posting while i was writing this,, Iagree with youfor the Elizabeth, i found a death entry for Elisabeth Wanen, with the name Allan/David Allan in the extra name added on 28.7.1822 in St Cuthbert's Edinburgh Midlothian.