Gengis,
Between now and the date the AAIB report is going to come out there is the summer display season, so I don't think it is unreasonable for the CAA to put the measures in now. You will probably find some display pilots and organisers will still have to scrabble about to meet the new restrictions and approvals in time, anyway!
I am sure this 'final' report may end up being adjusted in the detail following feedback from this year's displays, and the eventual AAIB report findings.
Flug