I did a search and found a couple of threads but none contained exactly what I am looking for.

In NSW, what are the requirements for having a battery in the boot?

I think you need:
- the battery in a box
- the battery box clamped to the car

Is something like a tie down strap enough or does it need bolts?

I just fitted a new 600CCA battery to the Escort (a battery that can turn over the engine finally), into the commercial-off-the-shelf battery box in the boot, and the lid sits on the box. A strap comes over the box and fixes at the front like a helmet strap would.

I assume this should be ok for rego but if there are other requirements it would be good to sort them out before I head down for a blue slip. Any help would be great!

Dunno about NSW but most states require the batery to be a totally sealed version or else one with a breather tube to the outside of the boot.

I found this on another site.

No its easy, the battery emits Hydrogen when charged, keep that in an enclosed space, get a spark & little bits of driver spread all over the place.

You can put the battery in the car as long as you seal the holes for the cable were it runs to the battery and wither put a sealed battery or a sealed battery box vents to the atmosphere out side the car for a normal lead acid battery.

RN: There is no ADR regarding the fitment of a battery.

The marine box is OK provided you seal it so it only vents outside the car.

im a reformed ex ACT Government employed rego inspector.

Thanks for taking the time to reply.