Oil fired worcester bosch heatslave boiler not igniting?

After 3 hour power loss/low voltege (84v) boiler would not ignite. Checked fuses, ok. Pressed both reset buttons to no avail. No warning lights on. Pump and fan working. Plenty of oil. System pressure normal. Thermostat settings working as normal. Programmer working normally. Just no ignition when the fan comes on and of course no heat.
Any ideas please?