It seems that The Dead Mac Scrolls doesn't refer to the Plus specifically, and doesn't say much about INTERNATIONAL boards.
The Macintosh Upgrade & Repair Secrets, also written by Larry Pina, does mention INTERNATIONAL boards in Chapter 6 "Dead Sets" (which is the problem my Plus has, intermittently) yet it still only shows the layout of the the US board, as shown, with the positions of Q11 and Q10 in opposite places to the INTERNATIONAL boards.
So I'm going to follow this book instead.
And finally, my board has the following message printed along the bottom shown in the last image