Thanks magna buff for noticing the finesse (it just about doubles the valur of the car).
I think the same relays are available with all sorts of contact and coil ratings, on Ebay as well as other Retail outlets.
They pull in from 8 volts to 25 volts with minimal coil current.

There is even an LED indicator built in (but no flyback diode!), strangely the socket is wired incorrectly for the indicator (black to +ve!).

Back to my Verada fuel tank project, will update that soon (very interesting - to one or two people!).