At The Races Casino - powered by Genting.
This could be a white label issue.
You may already have claimed this bonus, or similar, at another of their "powered by Genting" white labels. They don't list them, so it is hard, if not impossible, for a player to determine whether this is the case, other than finding "powered by Genting" on the website.
The bonus is advertised as being for "all new players", so to claim it is by invite only, and doesn't have to be granted to a new player, is misleading advertising.
Ireland is not in the list of countries prohibited from claiming the bonus.
The software is Playtech, and such problems are common because they have a central database. You could have been "blacklisted" by ANY Playtech casino, whether or not connected to Genting, and this would cause your account to be flagged as "bonus abuser" by Playtech almost the second it was registered. Since this database does not exist officially, but the Grand Duke let the cat out of the bag by explaining why they took a similar course of action with a new player, the casino would rather burn in bad PR than admit there IS a central Playtech database of "bonus abusers" that can be tied into any casino's registration procedures.
Many Playtech casinos automatically assume
ALL British players are only there to abuse the bonus, and thus may have confused Ireland with the UK and classed you as "British", and thus only out to abuse the bonus. This is a particular problem with Playtech white label casinos, which are often run using well known brands by license, rather than actually being run by the branded company, in this case Genting. Many of these white labels seem to be run from a call centre in the Phillipines, and data about players is shared between them all, and easily, since all are run from the same offices.
You would get better service from one of the Playtech casinos listed here in the accredited section. They are run by experienced operators, and are not white labels run from some call centre on behalf of some company that has bought the rights to use a brand, and farmed the running out to a call centre in the Phillipines, Israel, etc.
Incidentally, William Hill casinos has little to do with the William Hill bookies you might see on the high street. It is another of these branded white label casinos, and is run from call centres in Israel and the Philipines. The company behind it is called William Hill online, but William Hill only have a part share in it, the other partner being Playtech itself. Even this arrangement has not kept it clear of controversy, as it seems William Hill themselves have only limited say in what happens, even when the actions of it's branded online offering damages the main brand of high street betting shops.
You could even find the nearest Genting land casino, and give it's manager a piece of your mind.
This is not the first time a complaint has been aired here about one of the Genting online casinos, and it seemed quite a surprise given the esteem in which this brand is held when it comes to land casinos.