Looking to buy a 1994 Disco which has around 80,000 miles on the clock and has basically been very low use vehicle for many years. 300 TDI with receipt to show that the timing belt was changed in 2002 at around 60,000 miles, so on a mileage basis it shouldn't need changing now but is now 10 years since the first change. So my question is should it now be changed because of age or should it be good for at least another 20,000 miles?

Anyone seen any 'official' recommendations on this?

Belts are generally time or miles, whichever comes first.

Belt on a 300 isn't a big job at all if you have a few cheap but specialist tools. If you're that way inclined the whole set of tools and a belt kit will probably still be cheaper than paying someone else to do it, and then you'll have the tools for next time also.

Rough guess £150 or so for tools and belt kit. Less than £200 with reasonable certainty.

Ps.

I forget when the crank sprocket revision was on the 300, but you may need the update belt kit that has the new sprocket also. You (or anyone else) will not know that with certainty before the cover comes off.

(Unless the revision was after 2002 I guess...)