Ford Transit 2004 Problems

The people who sold you the vehicle have a legal responsibility under our consumer laws to find the fault and fix it. It clearly is not in a fit state to use while this fault is present. If that vendor is Ford, Ford should fix it. If it is the motorhome manufacturer, they should fix it. Either way it needs to be fixed, and must be under our laws. The fact that the engine can be restarted once it's been moved suggests that the system is being reset after falsely detecting a fault, and is electronic as you suspect.

The engine would run on bio-diesel, but if you swap you should service it and replace filters etc. after running a tank of bio through it. The bio-diesel will remove all the varnish that's built up in the fuel system and that will accumulate in the filters. It should be fine after doing that service, but I wouldn't advise doing it unless you can get bio-diesel wherever you go. It's not a good idea to be switching back and forth. A "Power Chip" is claimed to improve the economy, but you need to drive accordingly to achieve the claimed improvement. Most people don't get the economy benefits because they make use of the increase in power it also delivers.  Fitting a second reserve tank would be a good move, that way you can take advantage of price swings and buy when the fuel is cheapest; you can also buy in the major centres where the rice is usually lower than in remote areas and the quality more reliable. Transits are prone to turbo failure, so I would have the dealer check that before you go bush.