1830 John Lankshear marriage Margaret Smith at Westminster, Middlesex

1830 John Lankshear marriage Margaret Smith at Westminster, Middlesex

I know John Lankshear married Margaret Pearson in 1808 and I have not found a death for her - difficult in London prior 1837.
So it is vague to know if 1830 Margaret Smith is marrying that John or someone else. Later census have John and Margaret but which Margaret.
The census one is from Scotland. Any ideas?