Wouldn't necassarily agree with the others. Depends how many people you are taking / how much kit. If there is only two of you then the Discovery should be fine. If there are more of you or you are carry very large amounts of kit then it might be worth going for a Defener. I would query the benefits of the Defender you have mentioned, 240k on the clock is a reasonable amount of milage for any vehicle. Its one thing for this to be run up on the motorway but another to be done in arduous conditions which will put more strain on the vehicle. You need to have a really good look at the Defender and see wha the general conditions are like. Not much point having a roof tent and long range tanks if the engine packs in.
Also you made the point that buying the Defender would cost about the same as modifying the Discovery. However the discovery mods would be brand new where as how much wear and tear have the defender mods already experianced.
Bottom line, both vehicles will be more than capable of doing the trans africa. Because you are talking about two older vehicles with significant mileage, you possibly need to avoid direct comparisions between the Defender and Discovery in general and compare the specifics of the two particular vehicles in question. Whilst a Defender may be more suitable in general, this one may not be.
[This message has been edited by Toby2 (edited 16 March 2004).]