Hi Scousy, just looked at my Haynes manual, if it can be trusted.
Any 5W fork oil ..........or Yamaha's own is apparently called '01' according to Haynes
2001 - 2002 European models have 440cc per leg
2003 - on models have 435cc per leg
The Fork oil level is 140mm measured from the top of the tube with the fork spring removed and the leg fully compressed.
NB - Euro Model Codes 2001 is 5LV1
2002 is 5LV8
2003 is 5LVF so check yours first in case it's a 2002 registered on an 'o3 plate