Fixed.....

Things started off well. Even a cup of phone death next to the work area. That was my level of confidence.

Back up phone ready, just in case it goes horribly wrong.  Not sure if I could work physical buttons any more.  Why did we not realise we were living like animals 2 or 3 years ago!

Brute forced the thing apart and had a look around this wonder of the modern world.

Going well so far, whip that bit out at the bottom and replace it.  Couldn't be easier!  Job done in mere minutes.

Slap it back together and here is the result-

My fishes are swimming happily again, no random buzzing and all is good with the world.

But

If we look at the phone signal at the top....there isn't one.

The phone has since been pulled apart and put together a dozen times to fix.

Still not working

Update: Got new parts and it's now working.  What a pain in the tits that whole episode was.  Don't put your phone in tea.  Just don't.