By Ariane Sohrabi-Shiraz Many people celebrating St Patrick’s Day will today be attempting the Guinness Challenge – but which version will you be following? St Patrick’s Day is marked every year on March 17 all over the world, but especially in Northern Ireland and Ireland, where it’s a public holiday. The day itself honours Ireland’s saint, Saint Patrick, but it’s generally seen as a global celebration of Irish culture – with parades, food, drink and all things green. It’s estimated that a whopping 13 million pints of Guinness, which is often seen as the country’s national drink, will be cons…