Thanks, Garyj.
I see from the Bootcamp website that:
"To use Boot Camp, you need:
"An Intel-based Mac with a built-in or external USB keyboard, and a built-in trackpad or USB mouse."
I don't think this would apply to the new iMac, which has an external keyboard and mouse, neither of which is connected through a USB socket. In any case, this is a dual-boot solution, which I don't find attractive.
Are you able to run a Windows version of BIAB in the Parallels environment without any glitches? This looks like the route I would take.
Michael