Dear Aghadowey, PRONI has been my only source for the marriage certificate. PRONI doesn't have his birth, so I am thinking it was somewhere else, which I cannot find

So this is all that I have been able to find:
30/06/1909 marriage Robert John Martin to Clara Jane Turner.
Robert was a 'motor driver' and was living at Portsush at the time of the marriage
Clare Jane was a 'post mistress' and was living at Swatragh at the time of the marriage
Robert John Martin's father was Robert John Martin (labourer)
Clara Jane's father was William Turner (school teacher)
Witnesses are Robert Alexander Houston & William B Lurrat (I cannot read this writing)
