good evening chaps and chapessses

Defender Td5 Toad ai606 alarm fault. Indicators on passenger side not flashing when setting and disarming alarm any ideas

The indicator circuit in the alarm is fused. But it is just one fuse for the both sides. So if one side is still working it isn't that.
The alarm flashes the lights by pulsing the car's standard circuit wires. You could try to trace the wires to look for breaks. Indicator wires out of the alarm are black/white and black/green.