Whenever we buy anything we take a risk but consumer products sold in the UK have to meet certain safety standards whereas products which are sold from who knows where may well fall short of those standards and the retailer difficult to pursue due to his location.The radio was bought from Argos
Fully understand that. So why didn't you buy your replacement adapter from a UK supplier such as Maplins?
As an aside does your new radio include DAB+, unlike your old one which didn't? If not you will soon find it no longer works and will need replacing again. DAB+ is the latest generation of DAB (which is now 20 year old technology). Most countries have already converted to DAB+ and the UK will eventually. There are already new stations in most areas using DAB+ which an original DAB radio can't receive. Sadly shops such as Argos and most supermarkets are off loading original DAB only radios on an unsuspecting public