Had a go at fitting them today, as it wasn't quite so cold down in the workshop.
The location holes for switchgear etc. are different, but no great problem to drill new ones.
The main snag is that the brake reservoir fouls the instrument panel, so that needs to be raised/moved forward a bit. I had hoped that with the new bars being lower that wouldn't be a problem, but they are also a bit more forward, and have a degree or two more sweep back (all of which is good for my tastes). I'll also need to do a bit of re-routing of cable etc. to take up the slack, which may involve removing the tank. So while I'm doing that I may as well change the air filter, etc. etc. - isn't it funny how these jobs snowball?
Anyway, I've gone back to standard until the weather improves and I can spend a bit more time on the job.