Thanks for all the replies and suggestions - this thread kept on going whilst I was away on the holiday!!

I ended up ditching the flash, but took the lenses (17, 24-105, 100L, 70-200)... I haven't yet moved them across to my PC, but when I do I'll do a quick count of how many pictures I ended up taking with each and post back... I know the 100L macro never made it out of the bag, as predicted by several of you in the thread above! But I also missed the 85L on several occasions.