Except Irish tickets have to be claimed via a National Lottery agent in Ireland and that could result in difficulties claiming in the unlikely event they win anthing, and taxation issues in the exceedingly unlikely event that they win big.you could just buy some euromillions, that includes the UK. Not sure if you can buy them online via the UK lottery website
The rule with EuroMillions is that prizes have to be claimed in the country of purchase. There is no restriction on the nationality of purchasers. (Unless maybe you're a sanctioned Russian oligarch.) Prizes are tax free in all participating countries except Spain, Portugal and Switzerland. Depending on the laws of your home country, or anywhere else you're tax resident, you may have a tax liability there, but that's not the case for Ireland or the UK in any event.Except Irish tickets have to be claimed via a National Lottery agent in Ireland and that could result in difficulties claiming in the unlikely event they win anthing, and taxation issues in the exceedingly unlikely event that they win big.