right you can rule out the fuse, stalk, relay and stalk wiring, as all of these items are common to both front & rear indicators. Both the front indicator and sidelight are on the same wire from the fusebox (seperate wire for each side obviously

) but they have seperate earths so its most likely the signal wire at fault rather than the earth.
A1/2 and A2/4 are the pin numbers on the rear of the fusebox (see the fusebox faq for more info)
1st thing to check is you get voltage at the indicator/sidelight connectors, or just stuff another bulb in if you have any spare.
Does the car have an alarm by any chance?
edit: well you can rule out stalk/fuse/stalk wiring and relay if the wiring hasnt been chopped about with in the past, who knows what might have been done!