A quick update on this. I removed fuse box, cleaned it and pins as much as I could. Put it back in, same problem. Then I found a used fuse box on eBay and installed that one, but it too fried FL for starter motor. I used the multimeter to check the individual sockets in the fuse box for the starter motor relay and got a reading that didn't match the readings in the same sockets for the other relays.

So, I'm wondering if this points to the problem being somewhere in the harness, and I need to remove that entire harness? What's got me buggered is, my understanding of the starter circuit is that it has to get an 'OK' from the BCU first, then it sends a signal to the starter relay in the fuse box which closes the relay and allows current to the solenoid and starter (...recall that I initially found the melted wire to the solenoid and bypassed it with a new wire run to its pin in the fuse box...also Bendix spins when I cross the two starter leads with a screwdriver)

If I have this wrong, can someone please let me know? The circuit diagrams in the RAVE manual seem to suggest this as I read them, but I may be missing something. How likely is it, after all this, that the original melting sound I heard was the BCU? I removed the glove box and associated fascia to get a look, and the riot of harnesses and wires, as well as several mounted boxes, don't show any visible damage. Is there any way to test that particular function of the BCU other than finding the specific harness and pins and checking with meter?

Thanks to all for any thoughts on this.