chevvron,
US gallons. Would that it were thus!
Canada has been metric since the 70s. The price in the picture is CAD $ per litre.
ForeFlight shows Canadian prices in CAD $ per litre and US prices in US $ per US gallon. It's actually very annoying when flight planning border crossings and you are trying to find the cheapest Avgas.
Fuel prices are the most valuable feature of ForeFlight, for impoverished light-plane pilots, never mind all that magenta line nonsense!
Here are today's prices - Pitt Meadows is in the top centre.
The prices are colour-coded according to low-medium-high prices.
The $4.54 price at Bellingham is equivalent to CAD $1.59 per litre. The $5.47 price to the south (Skagit Regional - home to a great museum) is CAD $1.91 per litre.
The cowlings on the Ansons would indicate later marks such as 19 or 21, which could mean it is a post war photo.
You, like me, swallowed nvubu's bait - hook, line and sinker!
He posted screen grabs from "Angels One Five", which was made at Kenley in 1952. In retrospect, I did think there was something odd about size and style of the squadron codes.