I played around with that POI (Hickeys in Santry) and some other POIs. From what I have observed, the Nuvi 860T seems to be expecting a different set of fields than currently used. If I remove the city tag from a POI, then the phone number dials correctly. I had a look at the built in Garmin maps and for POIs there, whenever the city is given, it is immediately following by the county, e.g., Santry, County Dublin. So maybe that's the problem.