Now been doing it for a month and 10 days, replacing 1 or 2 meals a day with Huel.
Some weight loss, but according to my fat scales, reduction in percentage fat.
Luckily no gut issues, but did have a day of headaches, but that was cured by just drinking more liquid.
Discovered that mixing it the day before, and have it sit in the fridge over night does indeed improve texture, so not as "instant" as originally hoped, but 5 mins mixing just before bedtime, makes up 2/3 of the next days meal, so still a win with regards to time.