Essential (TIF) - Can we cover a customer departing from Dublin? 

Yes. Same rule as the other TIF policies. 

TIF have advised that we CAN offer insurance to customers that are residents of Northern Ireland but are flying from Southern Ireland (Dublin).

Providing that they are a UK resident and reside in the UK / Northern Ireland. As technically, the customer's trip starts in the UK, from their home address. However, just to reconfirm, we cannot cover customers that are residents of Southern Ireland.