Brownchurch were again a great help  - they gave me a list of everything I'd need for a complete lubricant change in case I lost oil from any component of the engine or transmission.

• 2x5 litre Oil - for a Landy 15W40 is recommended
• 1 litre Break/Clutch fluid (DOT4 - you can mix with DOT3 if it's all you can get, it just reduces the boiling point of the fluid a few degrees)
• 3 litres of Gearbox Oil - this is vehicle-specific; for a Discovery its ATF
• Transfer box oil - again it's vehicle-specific; for a Discovery its EP90
• Differential Oil
• Injector Cleaner
• WD40 - never travel without it....

I'd also take along some grease, (the spray stuff would be ideal for door mechanisms which I found to be prone to jamming in dry dusty conditions) and a small bottle of light oil.

Jerricans - I'd go for secondary tanks every time - but they are expensive and I've only had to use the jerricans in the Ténéré in earnest - the other times have all been out of choice (to avoid dodgy fuel stops).

Understand the issues of a lot of weight at the highest point of the vehicle (for the record Mandy rolled with only 20 litres in the eight jerricans). If you can live with that I'd recommend bolting the cans down to save them from damage as they move around, as well as for security - the use a siphon hose to fill your tank while leaving the jerricans in-situ. I know a lot of people use this method with great success, and some of them have not even rolled a vehicle yet. The hose will need to live outside of the vehicle unless you like the pervasive smell of diesel - get a dust proof box or bag for the purpose.

If you don't want to lock down the jerricans you will need a good strong back and a filler spout that you know actually fits your jerricans - there are variations out there. Avoid ex-MOD cans - as cans age or when they get damaged they may lose their internal coating and start rusting into you lovely clean fuel. Brownchurch give great deals on new jerricans, and their spout fits - but beware of the plastic bit at the end - mine is now lurking somewhere at the bottom of my fuel tank.

You can get funnels for filling with diesel, but in dusty or sandy conditions these are going to encourage contamination. And on the subject of dirty fuel - and there is a lot of it out there - I'd recommend a filter for filling from other people's drums or jerricans - I don't know if one is commercially available but a bit of wire gauze and fine cloth on a funnel would be a start.