Assuming Protestant. The registrations of Church of Ireland
marriages 1845-1982. There are marriages for Robert Bredon. Robert Hart but none to Hester.
Do you have any dates?
There is only one Bredon in Armagh in 1862's Griffith Valuation named Alexander Bredon renting from the Duke of Manchester.
Look up 1824 & 1846 Directories and no Sir Bredon or Hart
there is a heading of Nobility and Gentry
2 Robert Bredin births from 1864+ neither in Armagh.
Nothing in the Registry of Deeds for Ireland for either Robert Bredon or Robert Hart.
Although in the Prerogate Wills Index. there is a Robert
Bredon (1856) and a Robert Breedon (1810)
The Northern Ireland telephone book has 11 Bredin spellings, Londonderry, Belfast, Coleraine, Strabane.
Unable to help you.