Hey Fraz, welcome to the Huel Community 
great to have you on the team!
Thanks for your comments and I’m so pleased that Huel is going well for you. Congratulations on your weight loss so far, those last 10lbs don’t stand a chance!
Do you mean the ones that attach to the bottom of the shaker? Spare compartments is something that has been talked about a few times, the thing is that
a) usually they are designed for protein powder, which you need less of (~30g/portion), whereas Huel requires far more (>100g/portion). Therefore Huel doesn’t fit in.
b) If there are some that Huel fits into, when you attach them to the bottom of the shaker the shaker becomes gigantic (like artillery round size!) and is usually compensated for by a slightly smaller shaker.
I like the idea of Huel ‘tupperwear’. Perhaps a metal seal-able container with Huel logo debossed onto it. Would need designing though so that it was easy to decant into the shaker.