Gaffa Tape, Tenacious Tape, cable ties and a few metres of electric cable and you should be able to fix most things.
I presume you carry a spare wheel and bulbs anyway as well as a basic tool kit.
We have a spare wheel for the van but not the car. Bulbs we have I should have said. Gaffa's a good idea not heard of tenacious but again a good idea (we had a tent stanleyed by some yobs near Bordeaux once)
As well is two words!
How does a sage know everything about everything? or does he? or does he just think he does?
Remember, if you buy something you bought it, not brought it.
Wd40 is a must for me, you can now buy tiny cans. Can do 101 jobs.
Spare gas bottle / pig tail washers.
Socket and wheel brace for undoing trailer wheel nuts.
Adjustable spanner and a screwdriver that has different bits/ heads (called super tool in our house).
Having done a similar trip years ago. Some basic tools help and a decent (folding) wheel brace. Then as suggested by previous posters araldite, tank tape, insulating tape, short length of 7 core electrical cable plus some choc/block. Pack of ty wraps in different sizes. Cheap electrical test meter.
If you feel competent some spare rubber gas hose and jubilee clips.
Finally would also suggest some spare wheel nuts, some sizes can be difficult to get hold of.
You can cope without the water pump if it fails but it would be a pain.
Difficult to replace abroad.
When I first got my FC an old hand suggested I get a spare. I did, it seemed logical.
Naturally I have not used it!