Hi Monsoon - I used Allgas (allgas.ie) when we bought and renovated our house (3 new bathrooms & new boiler). No connection, just found them good value and professional. Very happy with the job and used them to insulate our attic since.
Dublin Tile and Bathroom Centre in Tallaght,good place and bargains a plenty to be had.They supplied the kitchen,ensuite and bathroom tiles for our new build.Also got the marble floor tiles off them too.
We ended up going back to them when it was time to fit the house out,and we got a great deal on a bath,large shower tray,2 toilets and 2 basins with taps.