Took apart two bad sirens - my old random squealer and a completely dead salvage. Cleaned up the circuit board on my old one and swapped in a couple of parts from the dead one. Reinstalled it & so far so good....it works....I guess now we just wait to see if it wakes the neighbours at 4AM.
Fitted the drivers side wiper grommet thingey while I was under the cowl again too. Hopefully that's the last time I'm under there for a long time.