Seeking information on British "medic" canteen

[Flying10uk]

I thought that British medics used the standard type, British military, water bottle during WW2.

In the UK we have "water bottles" which our American cousins refer to as "canteens". Generally if the "water holding vessel" is British I refer to it as a "water bottle" but if it is American, generally, I will refer to it as a "canteen".

I wonder if BEAR is on the right track because, as I understand it, brandy use to administered as a first aid treatment/treatment in an aid post, before modern drugs were available. We may laugh about it today but I believe it was common practice in the past. Presumably the brandy was stored in something and presumably the amount given to a patient was strictly controlled.