I wanted to do 6 intervals but got quite dark, despite me starting earlier, on the way back on No. 4 so stopped there as I had no headlamp. Quite happy with the pace, I think I would have passed level 37 too as all 4 intervals were sub 4-min (level 35 is 4:07, 36 is 4:02, level 37 is 3:57).
Gradually declined with speed (as expected) so may not have been able to keep it sub 4m pace for all 6 intervals if I attempted all 6, but happy to get my speed back to where it was before the long training sessions, so overall this is progression.