Definately timing belt , every other timing belt it is a good idea to replace the idler and the water pump, if they havn't gone to hydralic lifters(which I doubt, but we don't have any diesels that new on this side of the pond) valves need adjusting every 15000 miles. Fuel filters about twice as often ( or more as needed ) as recommended, fill new filter with ATF to clean injectors and pump. if using petrolium oil, change it and filter every 1500 miles , if synthetic (highly recommended),change it and filter every 7000 miles.
If it starts getting a bit sluggish starting in the morning , it's probably time for new glow plugs, but also on engines with over 125000 miles on them , check engine rotation speed for signs of starter wearing out ( it will start turning too slow to start the engine eventually . easy to check . put a white mark on the pump timing belt and have some one crank the engine. count how many revoloutions in exactly 15 seconds, multiply by 4, then that figure by 2.
this will tell you the cranking speed, it should be beter than 200-250 rpm ( hint, if you can actually count it, it's running too slow and is wearing out )

For some reason the slow starter thing is not in the books, but I have seen a number of them get parked over this one.
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-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel