//I’ve given up debating the science because, as I am constantly told, “the science is done”. In fact nothing is further from the truth but I can’t be bothered to argue the point.//
Just a brief comment on that one. To some extent I agree with you, and both sides of the debate have to be careful here that they don't over- or underplay the "done-ness" of the current state of Climate Science -- although it applies to every field, really.
No Science in any field is "done". There are always improvements to be made, gaps in the models to be filled, new theoretical breakthroughs to be discovered and more data to gather and analyse, squeezing the uncertainty in predictions and measurements. So it's never done. On the other hand, saying that can sometimes imply that there is a greater uncertainty about the current state of affairs than is actually the case. Taking my field as an example, the science is "done" in the sense that an stupidly huge volume of data can be very well-described using a single model that has been largely unchanged for the last fifty-odd years, with most of the progress since then being in learning how to use that model to spit out predictive numbers. There's plenty of such work still to be done, but the important message is that the model itself is, as far as it goes, undeniably a good description of nature.
On the other hand, it's not a complete model so there is also work to be done to find how to improve it (see pretty much every particle physics talk in the last ten years for a full description of the outstanding problems and potential solutions, eg
http://www.americanscientist.org/issues/feature/2015/2/what-next-for-particle-physics/1 ). And in that sense the science is not done either. But, again, that the current state of affairs is incomplete doesn't mean that the current state of Science can be safely regarded as possibly completely wrong. Just ... not complete. Nor will it ever be.
In essence this is true in Climate Science as well. By about now, a number of things have been established beyond doubt, such as the links between global climate and various contributing factors including CO2 levels (as well as longer-term cycles based on, say, solar activity or the irregularity of the Earth's orbit); and, further, there's a clearly established link between human activity and increasing levels of greenhouse gases -- and not only CO2, but also such gases as methane, ozone and CFCs (the last in particular being undeniably down to human activity as CFCs do not exist in nature at all). Mainly CO2, though.
The Science in that respect is, indeed, essentially done. The conceptual aspect that human activity can and does have an impact, is done. That, anyway, there is a finite supply of the problem sources of energy that is expected to run out, or become no longer economically viable to exploit, is also done -- so that even if the planet didn't give two hoots about fossil fuels being used up we'd have to think of ways to stop replying on them anyway. Plenty is not done: the scale of the impact, the nature of it, a complete understanding of the interplay between various components of the world's climate, improved measuring techniques, etc etc.
In some sense, the only way to really understand how the climate is impacted by human activity is to not bother doing anything, carry on as we are now, and see what happens. Such an experiment is, to say the least, highly inadvisable. Still, at least it would be "done" then, to everybody's satisfaction. For myself, I'd prefer to understand the impact of working to reduce the human contribution. At the very least, it stands a better chance of being rather less messy.