Our missing convict, Edward DOYLE.

G'Day from Down Under (Australia),

I am currently researching my granddaughter's paternal ancestry which includes a convict by the name of Edward DOYLE. According to his records, he was born in Thomastown, Roscommon anywhere between 1793-1803, and possibly the son of Michael and Margaret DOYLE. His parent's details are from a death certificate so this information is tenuous at best and his year of birth changes with every record, the average years being 1796-1800.

Edward was convicted of sheep stealing and was tried in Roscommon, he departed from Cork on the 28th of May 1819 onboard the "Daphne", bound for Sydney Cove, New South Wales, Australia for a term of 7 years. I have been unable to find a website to search for his trial details?

I have thoroughly searched Ancestry, FindMyPast, and FamilySearch for any birth records. Through FindMyPast I found and searched the Catholic Parish Registers from NLI and did find an Edmundeen DOYLE, son of Michael DOYLE and Bridget CURLY baptised on 5 July 1807, unfortunately, it does not give a day of birth and the infant may, or may not, have been a newborn. I do NOT believe that this infant is the Edward DOYLE who was convicted in 1819, my only reasoning being that the average year of birth, as stated above, was 1796-1800. IF he was born in, or around 1806-1807, he would still have been a child when convicted and that would have been noted on his conviction record.

It has been next to impossible for me to locate any records of Thomastown, Roscommon, which is on nearly every record as his place of birth.

Could anyone please advise me on how I might find this elusive convict's birth details and parents etc as well as his trial or conviction records? I would REALLY appreciate some help with this if possible? 

Many, MANY thanks, 
Erynne Baynes, 

Warragul, Victoria, Australia.