The Brook Community Garden Composting
I thought I'd share some information about our Brook Community Garden composting hub at Mitchelton. More than happy to take suggestions and answer any questions.
We previously had homemade bays from pallets, but Mark and Clytie kindly supported us in getting some new bays a few months ago which have been a great improvement for us. This is our setup, with 3 collection bins (daleks) and three bays.
Our process
Every two weeks we have 2-3 people volunteer to move the compost from our collection bins into the bays. We are lucky to be co-located with a community garden and we do this as part of our working bees. We find that leaving the collected scraps any longer gets too much to handle (and very smelly), as we get 2-3 full bins each fortnight.
It's not the most popular task at the working bees, so it is usually relies on the same people to look after it. I use a chalk pen to write on our panels the date and what went in to the bay as a matter of interest. 
We use a compost aerator tool to turn the compost fortnightly in the maturing bays.
After 6-8 weeks the compost is mature enough to use. It goes directly into our garden beds at the community garden.
Challenges
One of our challenges is getting enough carbon (shredded paper etc) to use when we fill up the bays with collected scraps. We would love to use so much more that we currently do. We are often putting out calls on the local Buy Nothing Group for shredded paper, but we'd prefer to have a steady supply from somewhere. We've also set up a storage bay nearby for locals to drop off paper.
Unfortunately we had a complaint from a neighbour about the smell that happens as we empty the collection bins, but we have explained it's very temporary (only about 30 mins) each fortnight. We are trialling adding lime as we move the the compost around to see if that helps with the smell.
We also seem to get a lot of the compost bags that are marketed as compostable.
Overall we've settled into a rhythm that's working for now, but it took lots of trial and error (and looking at other composting hub setups!). A key factor has been having two people that champion it together and do the regular manual labour required.