Train in NI myself.
I don't know of any regular Escrima classes, but there are some options. There are two guys in Ballymena who teach Escrima privately:http://www.imma-ni.com/http://www.silateurope.com/wordpress/?page_id=11
Closer to Belfast, there are some alternatives that although not escrima, may not be a million miles away (they are SE Asian MA).
There was a guy in Belfast who taught Satria arts. Basically he was a student on Steven Benitez and studied under him for a long time. He teaches in the city now (sent you a PM about it, check your mail).
There is also a Krabi Krabong class in Belfast too:http://sheranmuaythai.webs.com/
There is a Wing Chun teacher in Belfast too whose teacher in Dublin also teaches escrima. It may be worth checking with him:http://www.wingtsunireland.com/belfast-school/