Well, I fixed my drive. I gleaned enough from this forum and others to make it work.
The
N1 command didn't seem to help (I think); it returned:
Init SMART Fail
LED:000000CC FAddr:0024E2DB
I cycled the power a few times, tried the spin down/spin up sequences... then finally tried at the "F3 T" prompt>
m0,2,2,0,0,0,0,22.
Plugged the unit back into my USB-SATA (and IDE) adaptor unit and lo and behold; it was recognized by Windows (hoorah!). Busy copying files off it now.
For what it is worth - I found that USB-SATA unit very handy, especially as it has a separate power supply with switch. It also helped that I had a 2mm pitch socket connector lying around (I work in an electronics laboratory) that I soldered to some 0.1" pitch pins that I then stuck into the end of a spare "CD-Audio" cable - the type that you might have lying around from the days when you needed to connect your internal CD/DVD drive to the motherboard... what is nice about that connector is it is easily modified (moving the wire positions). Anyway, added power to the TTL converter, hooked it all up and made it go. Woo hoo.
Oh, and thanks to all who replied...