[FatBoy]

Many thanks or the replies. I already have a battery isolator, but I wanted an automatic switch, just in case I was incapacitated in the crash and couldn't throw the isolator switch.
The inertia switch seems to be what I need. I already have a switch for the fuel pump on the dash, so wiring in an inertia switch located behind the dashbord should be pretty straightforward.

Thanks again.
Paul