Considerable effort was made in the AAIB report to cover possible altimeter, ASI errors and power setting readings. The AAIB report found many faults, but none of them could be construed as being primarily responsible for the crash.
The question that is likely to be asked of any jury is whether the pilot was reckless in continuing the loop maneouver when it became apparent that the minimum gate height had not been achieved at the top of the loop?
An experienced pilot should be aware of their approximate altitude even without the aid of cockpit instruments.
If lack of practice time due to fuel, cost, and timed life component restraints rendered the pilot's judgement of altitude and attitude unreliable, should they have attempted recovery or continued the maneouvre immediately it became apparent something was going wrong with the display?
Perhaps the flying costs would only be covered by the display organisers if the full display sequence was flown?
Finally, was the pilot fully briefed and aware of airspace restrictions and correct exit routes in event of an in flight emergency. This is also covered to some extent in the AAIB report.
If you just read the AAIB report, one might be drawn to some quite damning conclusions. The important thing to bear in mind is that nothing in that report can be used in court and AAIB reports can not be used to prove or demonstrate fault or liability. Any evidence presented must be from an independent investigation conducted by the police and they will have a much harder job of creating a watertight case for the CPS to take to court.