Is over-50s specialist Saga axing its popular platinum credit card because of Brexit? The card is run for Saga by a Dublin-based bank and is closing on 28 March, hours before the UK is scheduled to leave the EU. The Saga platinum credit card has long been a popular choice among people who travel abroad because it doesn’t charge currency conversion fees. Other benefits include up to 55 days of interest-free cash withdrawals, discounts on Saga holidays and cruises, and…