Bobby Irvine actually played for Northern Ireland and got the first of his 8 caps while playing for Linfield in the early 60's.
We also had an Irish Goalkeeper in around 1964 called Mick Smyth who was brilliant for us and ex Man U trialist but went back to live in Dublin going on to play twice for the Republic of Ireland.
Worst keeper ever has to be Paddy Roche who Manchester United signed from Shelbourne as a replacement for Alex Stepney in the mid 70's.
Known as the Galic Fish, his clangers cost United vital points that could have won the League title and also a clanger for Ireland against Switzerland put paid to Euro qualification. Due to Paddy's form Gary Bailey got his chance at United at a very young age for a Goalkeeper. Paddy lived in Sale, and I was told was a lovely bloke, but thankfully was not one of the many ex-United keepers that came to Alty afterwards.