Hi Woz,
I think you should consider a Complex Interface Adapter swap ( long for CIA :-D ) This way you might be able to get your amiga back up but not for 100%. Simpel just take it out of the socket and change it with the other one. And power it up
I once blew up my cia due to a printercable. I tested it then by swapping the CIA, it worked but still needed a new one.
Hope this helps
Greetzzz Henk