Hi Hawfinch/Plantmark,
I like most of us constructed my own Bins. They are 1mx1mx1m with 5mm mesh sides and a wooden lid. The Bins sit directly on the ground.
The lid keeps the worst of the rainfall off the pile and helps to conserve some of the heat whilst the mesh allows good airflow to the heap.
The sides of the heap tend to dry out quickly so it is essential to fork over the heap at least once a month (more often in summer/drier months to ensure even moisture through out.
After about 9 months I empty the bin into a finishing bin of similar dimensions with solid sides (with a few holes drilled to allow air flow) to complete the process which usually takes about 3 months where upon I bag these contents until I need it.
With this system at any given time I would have a current bin, a finishing bin and bags of finished compost ready for use.
I don’t turn the heap in the accepted manner but I do fork it over on a very regular basis.
In the colder wetter months I cover approx. 75% of the sides of the current bin with sheets of cardboard to conserve heat within the heap.
Don.