A deposit of 24% is not standard at all, but you are expected to have funds for stamp duty and legals as mentioned above. I would say that either this figure was an error, or the bank calculated that you will need a deposit of 24% to buy a property for the price that you advised, i.e. purchase price less mortgage approved = 24%.
Surely someone in the bank could answer this for you?
Best Regards,
Dave Curry, Irish Mortgage Corporation
https://ie.linkedin.com/in/davecurryirl