Still have a miss fire :(

[MarkX]

Last month I had a misfire on track under load. I read a code for the front O2 sensor, so it was changed as well as a new coil pack at the time. Yesterday I went to another track day and did one lap.......huge miss fire over 6k rpm and now occasionally won't start, not even a kick.....then suddenly fires.
Just looking for ideas on what to look at next, is there a way of testing the crank sensor?
:spanner:😧

 

[bloke]

as a general rule unless it's totally dead a crank sensor will play up when engine is hot and you try to re start it.