Good point about the running
I was going to keep the intervals either on the bike or in the gym (more controlled and safer) and just run with the dismount/remount training, but as my running is quite poor it's probably a good idea to do more of it.
Cheers for the suggestions and reassurance. I actually watched this race last year and it looked quite serious but it is on Boxing Day, so people have to be hung over and bloated right?