The price difference is largely to do with the ACCU market being...

The price difference is largely to do with the ACCU market being voluntary, until the safe guard mechanism kicks in for our largest emitters. In the EU, there is mandatory purchasing and foreign operations can't buy ACCU for retiring. The ACCUs purpose is to abate Australia's emissions, as are ETS units for the EU. So its not a typical commodity market where everything is substitutable. Then theres methodology, reputation and desirable co-benefit differences between various credits and methods. I also expect government pressure and social license pressure to limit the amount our biggest emitters buy from foreign carbon markets into the future or from 'other' methodologies, unless there is inadequate supply but the price of ACCUs already makes a lot of projects under various methods worth while and the number of project registrations has been jumping significantly. This is not a guarantee of supply of future credits by any means but generally theres reasonable cost in getting to the point of registration in the first place and a project developer, you would think, would be acting under the view that they will generate enough credits to justify the cost.
https://www.energycouncil.com.au/analysis/carbon-credits-will-they-continue-to-rise-in-price/ Old but useful. The major banks also publish good information about carbon markets. https://www.commbankresearch.com.au/apex/researcharticleviewv2?id=a0N4y00000lSe1V Again, 2022.

Last year the price pull back was a rule change to allow project owners an exit from future supply because the spot price was 3x their contracted price. So a lot, like LGI, paid to exit their contracts with the CER and sell at a higher price on the spot market.

I'm not a big fan of the cash position and paying dividends (after raising money) but it seems they hold onto large chunks of their certificates and I want to find out how long they generally hold on to them after being credited, why they hold what they have and is there any bias in crediting periods between financial halves for their project, do they credit evenly over the year or is it all in Feb.