tiled roof

hey i have a tiled roof which is 11 years old and there is a small leak in the lounge room it occurs when it rains of a heavy downpour on an angle, i got up on the roof and can see a water trail however i can't see exactly where its come from. Over the past ive had 2 roof repairers come and say its fixed though it still occurs, the tv antenna is close by approx 6 metres but it looks all sealed up am i better off trying my luck at another roof repairer or should i get a builder to have a look
thanks