Irish borrowers look at interest rates on offer in the UK, and on the continent, and feel hard done by. After cashback offers and charges, the average mortgage interest rate is 2.97 per cent in Ireland, compared to 2.1 per cent in Europe, according to a 2019 analysis by the Department of Finance. On a 30-year mortgage, that’s the difference between paying 51 per cent of the principal on interest payments, and 35 per cent. When you do the sums, it’s a sickening amount of money. So the news that Avantcard, the Spanish credit card company, is entering the Irish…