In case anyone else is looking for an option to hold a Trangia alcohol stove.
I found these Sistema brand "portion pods" at the supermarket:https://sistemaplastics.com/products/to-go/210ml-portionpod-2-pack-to-go
Have found that they are a near perfect fit for a Trangia stove.
A bit of carbon felt or some scourer pad inside the lid makes for a solid, rattle-proof, carry. The pad also works to soak up any small leakage from the stove if that occurs.
It's foodsafe HDPE so good for alcohol storage.
Keeps the taste of the fuel out of my cooking set and in a way I prefer to the plastic bag option. Obviously a plastic bag is cheaper, lighter etc. and for those who prefer that option all power to you. I just prefer a solid container because that's my preference.
Additional good news for me is the fact that the portion pods fit nicely inside a Stanley Adventure Two Cup Set:https://www.stanley1913.com/products/adventure-the-nesting-two-cup-cook-set
Anyway thought this coincidence of sizing might be of interest to someone else.