I guess you have a point Simon. However I believe this is the way they are doing it with nuclear disasters like Tschernobyl. the North Sea is like a Swiss cheese with many empty dry oilwells, why not utilise those wells. One of the tasks for the present investigation is to evaluate the condition of the mercuryflasks if they are at all movable. An interesting submarine detail is the way these 65 tonnes of mercury steelflasks are stored on board the U 864, they are stored in the box keel, I never realised they used the keel as cargohold. I bet the boat was pretty stiff at sea with 65 tonnes in the keel.
Tore