Thanks, GR2 - I think I made an error there, as you said. And now, having checked the 1841 census again, he is recorded as being born in Ayrshire; unless the recorder made an error, the Campbelltown birth cannot be his anyway! I think I'd better start another search...
And ColC: I do have the details of Edward's marriage to Margaret, but it seems now that, as above, he is not the same person as that born in Argyllshire. Do you have any information in that area?
I will follow up your suggestion re the Burns Monument Centre to try to find his death.
Thank again -
Andrea