Hello Carol,
I haven't found a marriage for your George Lee and Margaret Cullen but my sources for irregular marriages only go up to 1855. However, I see from the 1851 census that Margaret's father, Thomas, was a Chelsea Pensioner, and this looks like his marriage :
Mordington, 22 Jan 1836: Thomas Cullen of the Royal Artillery to Mary Jean Brown of Berwick. Wit. Robt. Patten, Mathew Trainor
Kath