Sorry I didn't spot this thread earlier.
Nick, the fuel prefilter idea is tricky on a td5 as the pump's in the tank and the system is quite high pressure. Not sure how you can get round that except by having a second tank and filling the main only from this one with a 12v pump via a filter. Anyone else found a better idea?
Roamingyak's right to get all the big stuff done before you leave. If the car's nearing 90,000miles/140,000km(?) and still on it's first dual mass flywheel I'd definitely get it changed - often the cause of multiple "mystery clutch failures" - one couple I met in Livingstone had changed their clutch 3 times in a month at different bush mechanics, when the actual problem was excessive play in the flywheel.
Change the fuel injector harness (inside the rocker cover) and carry a spare to avoid oil contamination of the loom and eventually the ecu. (Check the ecu red plug for oil as well) If the fuel pressure regulator above the starter motor is dripping fuel, change it, and if the starter is VERY wet with diesel, change this too. Note: you can get oil coming down from the rear camshaft hole plug in the head, which is not to be confused with diesel, and is less of a problem (also easily remedied by cleaning the area round the top gasket thoroughly and smearing Loctite flange sealant around the whole area, but if you're changing the wiring harness, the lid's off anyway so flange seal it all around the back including the halfmoon)
Good luck and safe travels,
Simon.