Just an update, as promised, on the previous thread...
I ran through my 90 minute set twice over the week before the gig, and had a bit of a tired throat for a couple of days. THe key changes in behaviour I addopted were to drink less caffine for the week (replacing it with water), and using a thyme and liquorice (sp?) herbal mix by a friend of the family. The gig went very well, i sold over £100 worth of C.D.'s, and the voice (just) held out. Although I was working quite hard at the end to stop myself sounding tired, the most noticable difference for me, from previous shorter gigs were I have paid less attention to my throat, was that I had no problems the following day. I often find I have a low rumbling voice for a couple of days afterwards. On this occaision my throat felt a bit tired, but otherwise no trouble!
So, thanks again for the advice and the good wishes. I've learnt to treat my voice with a bit of respect and seen good results from a little investment.