Actually, I took the thing apart at the weekend, and discovered that it is the aluminising coating completely gone from that spot
So now I will wait and see if it "grows"
The worry is now, for all those Lightbridges we have here in Oz, is mine just a bad one in the bunch, or have they all had sub-standard coatings put on them??
I guess, all you Lightbridge owners, have a close look at your mirror
