We concreted in some old railway sleepers to create the desired shape of the lawn before removing 3 inches of turf and top soil with our mini digger
5 tonnes of compacted Type 1 followed by layers of granite dust create the perfect base. This will be free draining but rock solid so the grass does not sink.
There are so many companies not using Type 1 because the ground is hard at the moment. It won’t be in the winter!