The first thing I would do is change the thermostat, just to be sure, the gauge cannot be relied upon to be completely accurate on a motor of this age, do you hear the fan roar on start up and does it go quiet after a few mins, Rick
If you do not get start up roar from your fan it may mean that the viscous fluid has leaked away which will mean that the fan will not be working, Rick
Your local motor factors are your best bet, you should have one not too far away, if that proves a problem then online such as Milners off road or other Jap 4 x 4 sites, Rick