Looks like I've been sleeping on the job! Aquamist have some new products kicking around, like this nice looking guage.
They've also brought out a bracket with all the required components pre-fitted and ready to be wired up inside the engine bay... looks great! So I'm obviously going to be busy doing some researching over the winter.
I need to find a tasteful way of incorporating that guage and my E-Boost guage into the Ghibli's dashboard!