I found marriage of Michael Dwyer and Catherine Croke, that is how Fr O,Carroll spelled it, in Clonoulty 11th Sept 1828 like you said.
Witnesses John Dwyer and Catherine Costelloe, address given was Ballagh, a village near the border with Knockavilla
Did you find baptism for Michael in 1828.
Will look up baptism for Margaret in May 1864, to se was there a different address.
Did they go to Australia and if they did , did you find them on a shipping list.
Best of luck with your research, let me know if you have any questions.
Christina Irelandxo Volunteer.