Yes that it, it was intended to keep a little “sharpness” for my winter C races, and an alternative workout in the week rather than my week being 8-9 of Z2 alone.
With regard to improvement I did of course mean improving my ability to complete the intervals, and on that basis WindWarrior your note is very helpful thanks; I’ve been approaching each interval as the maximum I could put out for 2 mins each time, rather than aiming for a 90%/340 watt average per interval. I’ll give that a try next week and hopefully have a little more success.