People,
Cheers for all your replies. I'll be going through the responses with my maintenance company.
I'm going to see if I can get the N1 guage swapped too - that's a good idea, but I'm (reasonably) confident that it isn't this because we have fired the machine once or twice and then aborted the start due to higher than normal TOT acceleration - which indicated to me that we hadn't achieved sufficient N1 in the first place. It's worth checking though.
Cheers team, any other ideas will be appreciated.
Joel