To remove the tank you have to undo the tank retaining nuts including one that comes down from the floor inside the car. Plus dismantling the inlet pipe from the filler cap assembly and carefully unplugging the sender unit leads. Not all that difficult.
If the leak is from the drain plug I would have thought that, if you can remove it, then simply putting it back with some sort of sealing mastic applied to the threads would cure the problem. But I don't know how easy the plug is to remove : never done it myself. Nor what sort of sealant would be correct.
But possibly your tank is corroding from the inside. Any water in the petrol will accumulate at the bottom of the tank (since water is heavier than petrol and they are essentially immiscible). In which case resealing the plug would only be a temporary cure. But it might get you round France. The tank sealant epoxy, if applied liberally round the plug area, would be a temporary buffer against further corrosion holing-through (which will only progress slowly anyway).
I am in HR8.
