After wondering where I’d attach my fuel tank earth to, I remembered there was a mounting on the nearside of the tank. Oops! One ring terminal (well, two) and bolt later, the tank was earthed.
Continuing with the random odd jobs I’ve been doing some work on securing the wiring loom. I dug out the relay mount that was removed from the Mazda and bolted it onto the chassis. I put it on the other way round originally. It looked tidier, but the wires were too close to the manifold for comfort, so it’s ugly way around unfortunately.