A brief summary of where the bottom green is at.
The underlying issue with the patches struggling to recover has been a root pest.
There have been concentrated numbers of the pest (nematodes) in those areas, and the disease has flared up every time the green has been under stress, whether environmental due to high temperatures or mechanical when the green was scarified.
The green has been treated to kill the nematodes, a plastic membrane has been placed over the areas to keep the ground warm and the grass is recovering well.
I have put in place a program for next season to make sure the problem does not reoccur.