In principle It's not difficult to assign value Nigel. You work out the benefits and/or risks of retaining whatever it is that you're looking to defend and then find a way to quantify that to an equivalent financial value. Economic benefits (such as tourism) are often done on a National basis whereas Social benefits can be done on a National or "Humanity" basis.

But this sort of forum format isn't suitable for that type of discussion. It might be worth putting in a holding set of arguments in the current consultation to try to open a foothold for the second round of consultations: I don't have a lot of time spare at the moment, but will look into it next week to see if it is feasible.