The example you provided is a day which OFCOURSE it would work well... The majority of days on the FTSE do not look like that perfect example and if you were to put any EMA or any system it probably would have made money that day... How about long when stochastics is overbought and Long when stochastics is oversold?
If you want to test a strategy, the best way to do it is look for the worst day possible, in an EMA's case, its very sideways choppy and see how it would have done then... If its breakeven or a little bit down then thats good, the occasional good day should make up for it. Most likely thought you would have lost over 200 pips on a choppster.