Thanks to all of you guys for your time and information...
I have a good idea now on what to use.

fully synthetic. It looks like brand wont have a large impact as long as I use the correct weight, and that seems to be 10w40 for the gear box.

Thanks
Dave

EDIT - just so your guys know, I have the wet clutch I think as its just the nsr 250R not the sp or se models, and its oil injected.