belinda earl was parachuted in to turn round the retailer 's sales slump .
today m&s said sales were up 0.7 % - the first time in almost four years .
food sales also up after retailer enjoys record valentine 's day sales .
glitches with its expensive website also fixed with sales up 13 % .
m&s shares up 20p this morning - first time above £ 5.50 since 2007 .