Indicator problem on 2000 vauxhall corsa

4 bulbs have gone now this year on the right side, since the last was replaced (by a mechanic) my indicators on just the right work but flash rapidly. now the right brake bulb has gone too. i havent yet checked the last bulb to be replaced was of the right voltage, but, saying it is, would i be right to consider the flasher unit under the bonnet in the relay box, if so i can do this myself with the help of haynes. failing that any ideas what else needs to be checked as i want to avoid the cost of a garage for something as simple as lights