LOWDEN - BROWN marriage

[Therese]

The witness at Thomas Brown and Ann Smith's wedding in 1831 was
HENRY LOWDEN (I understand it can also be spelt Loudon, Lowdan etc.)

I have now found in the births 1823 Rosemary Street Presbyterian Church
a birth  for John Lowdan 1 May 1823. Father is Henry Lowdan , mother is Margaret Brown. And according to the IGI there are also births for Margaret 1825, Mary Ann
1828  and Ellen 1839.

There is a possiblity that Thomas and Margaret could be brother and sister.
There is no marriage at Rosemary Street 1811-1823 for Henry and Margaret. I was
hoping to find Margaret's father's christian name.

Is anyone else researching the Lowden or Brown families?

All help and advice greatfully received.

Therese