I think I might have given Trent (active8fitness.com.au) a few clues on when I have reached my limits. It's fairly simple really and involves a bucket and me throwing up.

He seems to think that if I am struggling to keep the last sip of water down I am about at the right top end of training

The worst bit is he says it all with this big shit eating grin on his face. Correction the worst bit is I am paying him for it.