I don't know why i didn't think of this before - try adding 0.5 - 1.0 L of methylated spirits to the tank when you next fill up.
It's just occurred to me that there's a good chance you have condensation in the tank and it's built up to a level where it's causing a problem. Because petrol floats on water it's more likely to cause problems with a low/empty tank whereas with more fuel in the tank it's likely to get moved round more and be less of a problem.
The meths will form a sort of emulsion with the water which will allow it to be burnt with the rest of the fuel and in effect "dry" your tank out by removing the water.
Whether this will provide a total cure or not remains to be seen but for the cost and relative ease of trying it then it's definitely worth a try.
There may be those that hold their hands up in horror and say that meths will damage various seals etc in the fuel system. In larger quantities, prolonged use and/or higher concentrations this is probably true. However in this concentration it's just enough to remove the water without doing any damage to the rest of the system.
If it doesn't cure your problem you've only lost a few quid on the meths but you will have eliminated water from your fuel tank and a potential cause of the cutting out.
In fact i'm glad i thought of this, i need to treat my 760 to this and also a small dose of the same on my other two, just to be on the safe side.
