By Jess Jones The UK has shifted up the rankings of the largest global ad markets to third place, replacing Japan, and sitting just behind the US and China in Groupm’s end-of-year forecast. Growth in the UK’s ad market, which is the largest in Europe, is expected to grow by 4.4 per cent this year with an estimated revenue of £41.3bn, according to a forecast by WPP’s media investment group. It falls just shy of a previous 4.8 per cent projection and is slower than the overall global ad growth rate of 5.8 per cent. President of business intelligence at Groupm, Kate Scott-Dawkins, said the bump u…