Defender 110 is definitely larger inside than 80 series, also the boxy shape is easier to pack and more height in the Defender is much better for sleeping/living in with storage under bed.
80 series will use a lot more fuel and the majority will already have done high km so maintenance will be constant for both anyway. The only advantage of an 80 series travelling in Australia is that it’s a bit easier to find a mechanic who wants to work on your vehicle. Having said that, I’ve only ever been refused service on my Defender a few times LOL.

