I can't give you the name on the message board but there are memorial inscriptions for most of the counties on a UK website. You can contact me for the name. You would have to go through all the counties though and perhaps find nothing?
At least the name Masterson is different and only 48 of them in Ireland for the Griffith Valuations - a bit too late for you but there are Patrick's there, a son perhaps?
They are a bit of all over, but no Patrick in Roscommon. www.askaboutireland.ie
The only record I can think of that might capture someone
before 1830 is the Tithe's held at the National Archives in Dublin. They are not searchable online but you do find occasional records for them.You would certainly need a Parish before embarking on that as they are not digitized and you would need to scroll through tons of microfilm.
ps my mum loved Dorset if that is where you are from