The cost of living in Ireland is higher than the UK, but it's not that much higher.not defending TD's salaries or anything, but not sure about this "dividing by number of people served" rationale. surely there is many other factors to consider when comparing countries, cost of living etc.
I believe that the UK voters are under-represented and this leads to governments making decisions that are at odds with public sentiment and ultimately detaches the Parliament from the people.
However in Ireland you have the other extreme.
There are a huge number of backbench TDs who only serve local interests (which are largely not for the benefit of the voters). These TDs are afforded parliamentary powers which are then applied to local issues. These powers are often abused.
By having this level of representation means that Dáil Eireann is just a national local government.