thank you to everyone who has kindly replied to my mailing. i managed to find somewhere in the UK that had the part and got it couriered over, but as this is just the start of a long trip, i am sure that i will have use for these contacts again in the near future.
thanks to dave lambeth for the suggestions re the gear box. aware of this problem having read the lengthy thread over the past few weeks, i had the yamaha guys here in rome who seem very on top of things check my gear box out (actually they inspected the entire engine) and they said the gears looked fine. i also took a look at them, and the fifth gear didn't look any different to any of the other gears. maybe i am just lucky, or perhaps my gears have already been replaced, as my bike has done 52000 km (though i only got it with 44k on it). thanks for the advice!
...ships are safe in harbour, but that\'s not what they were built for...