Hello Wendy,
I descend from a cousin of William.
George Burnlees & Margaret Marshall had (with their names as per the OPRs):
George Brownlees (b.1775) m. Elizabeth Johnstone
Catharine Brownlees (b.1776)
Alexander Brownlees (b.1779)
John Brownlees (b.1781) m. Helen Haldane, d.1856
James Burnlees (b.1784) m. Isobel Currie
William Burnlees (b.1787)
Elizabeth Burnlees (b.1793) m. Peter Cairns, d.1873
Although I have not extensively researched this family, I'd be interested in adding a spouse / death date for William - especially if he moved to England. Ultimately I would like to create precise tree for the Brownlees of Greenlaw and I haven't previously found details for William.