Thanks all for the responses. It looks like its only the Servisair lounge that's accessible for us. BA seems to specifically exclude DUB as a destination for access to the International Lounge and specifically exclude DUB and domestic flyers from accessing the "UK and Ireland" lounge with oneworld cards according to their website.
The following copied and pasted from the BA website:
"Lounge information
The British Airways and bmi International Lounge
The lounge is located at Gate 5, and is open to the following customers travelling on international flights operated by British Airways and bmi (excluding Dublin):
British Airways flights:
Club Europe
Flexible Economy (Hanover flights only)
British Airways Executive Club Gold and Silver members
bmi Diamond Club Gold and Silver members
oneworld Emerald and Sapphire members
bmi flights:
bmi Business Class
bmi Diamond Club Gold and Silver members
British Airways Executive Club Gold and Silver members
The British Airways and bmi UK and Ireland Lounge
The lounge is located next to Gate 8, and is open to the following customers travelling on domestic bmi flights within the UK and to Dublin:
bmi Flexible Economy
bmi Diamond Club Gold and Silver members
British Airways Executive Club Gold and Silver members
Arrivals Lounge
The arrivals lounge is located in the Departure Hall on the Upper Level landside.
Access is by invitation only for customers arriving on bmi flights landing before 12:00 from Eastern Europe, Middle East, Africa and Asia.
The lounge is open from 05:00 until 14:00 for the following customers.
bmi Business Class
bmi Diamond Club Gold members"