Yes, I meant top 6 in this meeting, you got me all mixed up by bringing the GP's into it. Rules say top 6 qualify:
014.7.2 Race Format
The 16 rider, 20 heat format is utilised when the top 2 riders will be seeded direct to Heat 22 and the next 4 riders finishing positions 3rd to 6th, will compete in Heat 21 from which the top 2 will go forward to Heat 22.
Masters "finished" 5th
Kemp "finished" 7th
Masters, unfortunately, "withdrew" from the meeting, he wasn't excluded from the meeting.
They're the published regs, like @Gambosaid you must probably have an unpublished supplementary reg that none of us have seen?