Hi again Kate,
Seagoe Church of Ireland BMD records would be a good source.   I am snowed under at present but maybe someone else can do a look up for you.   If you have no luck, give me a shout in a few weeks and I will do it.   I do know that Valentine Burrell is buried in Seagoe cemetery as his grave is only a few away from one of my ancestors graves.    The records of Seagoe Cemetery are only searchable from 1901 however burials were taking place hundreds of years before that, hence I suggest the Church Records which date from the 1600's.  Drumcree Chuch of Ireland may also be worthwhile to search along with the graveyards in Lurgan . ie. Shankill and Lurgan Cemetery aka the New Cemetery even though it dates from the 1800's.  
http://www.lurganancestry.com/gravestones.htm  has the grave inscriptions for Valentine in Seagoe and also a Burrell in Shankill :-)   
 Regards, Barbara