For completeness, I searched my French-based LeShop for 'milchpulver'. Which gave me none of the previously mentioned babymilks, etc, but did throw up coconut milk powder. Which didn't appear in the previous search for 'lait' or 'poudre', despite having both in its title.

Trip to an actual shop it is, then. Curses - browsing supermarkets always makes me spend money.

kodokan