Done a few Europe tours, and would recommend:
Full toolkit, thermostat, gaffer tape, lots of tape, hose clips, cable ties, tin foil, 3x2 litre pop bottles full of water, oil top up, PlusGas/grease/PTFE/lubricant, sandpaper and file, string, rope, various bits of electrical wire, old coathanger, 35mm film containers with Swarfega, Vaseline, Gunk, talc, a good variety of self tapping srews, nuts, bolts and fixings, a big tyre lever or crow-bar, old rubber floor mat to lie/kneel on, magnetic extendable picker-upper, footpump, tyre weld, wind up torch and plug in 12v lantern.
I always take clingfilm and or clear plastic (like florists use) for broken grass repair, basic "My Naff Code Reader" diagnostics or similar reader (taking lap-top?).
Also the legal bits: all original car, personal, insurance and MOT docs, plus copies and set of copies left at home, hi-viz vest for each passenger, first aid kit, bulb kit, GB sticker or icon on reg. plates, fire extinguisher etc.
Also EHIC card, trip insurance, phrase books, spare camera with film and notebook for evidence gathering if you have accident.
Think that's most of it. Hope you've got an estate for all of the above
