Full Service
Your Vehicle needs to be in perfect mechanical order.
Tyres
When your tyres are in good condition and of a construction with good sidewalls (BFG MT and AT Michelin) one spare wheel is usually sufficient. If your Tyres have been repaired or you are unsure on this then to be safe replace them. No remoulds or retreads.
Toolkit
You should bring a base toolkit of good quality tools, containing at least a set of combined open end/ring spanners 8mm to 22mm, Socket set with ratchet and extensions, pliers set of screw drivers, Hammer ,Cutters, set of Allen Keys.
CB Radio
A Simple CB Radio is an essential item. As all kinds of two way radios are illegal in North Africa. I would suggest to install the CB radio in a position not noticeable from the outside and in a way that you can disconnect it easily and stow it away. Preferable that you don't use a handheld one.
Jerry Cans
Whether you opt for long range fuel tanks or jerry cans is a matter of personal choice.
Recovery Gear
Recovery points front and rear,Long rope or strop (25ft min) Shovel, Shackles, Hi Lift jack and sand ladders if you have them could come in handy but not essential to have, but just as good is 2 pices of carpert as this can roll up and store easy.
Spares
Spare shock absorber,
Fuses, Bulbs, Drive Belts (fan belt) Air filter, Fuel filter/s, Oil filter, Engine Oil Gearbox Oil, Differential Oil, and any other Oil's you may need, Brake Fluid, Universal Hosepipe's for cooling system, fuel pipe (universal), Spare Vehicle set of Keys, prop shaft UJ's.
Miscellaneous
Filter for Diesel filler nozzle (Land Rover TD5) Vehicles Operations Manual, 2xWarning Triangle, Jump Leads, Tie-down straps, Bungees, Map reading lamp, Torches, Spare Batteries (for torches) 2xFire Extinguisher
When you service your vehicle yourself, you will know what to do in preparation for such a journey, when you get your garage to service your vehicle, tell them what you are up to and that you will also be doing off road driving with the vehicle fully load.