@BigBoy Engineer replaced my IHD, said it would take a few hours, and agreed I Could ring him back late afternoon if no dice, he also tried three new IHD and spent a while to make sure it was connecting properly, he said the first two failed.
Ten minutes after he left, the live usage is working
So now I can do proper checking of everything in my home, thanks for your advice man which helped here.
I still have the old IHD he had no interest in picking it up, so will probably chuck it away.
Interesting my 1000w rated kettle consumes 2100w. Mislabelled product I guess.
Ten minutes after he left, the live usage is working

I still have the old IHD he had no interest in picking it up, so will probably chuck it away.
Interesting my 1000w rated kettle consumes 2100w. Mislabelled product I guess.