They'll pass muster, good work Glenn. Perhaps a little wide in diameter, as they were "long and thin", being only 44 gal, but they should look OK once in place. Alternatively, i think there may still be a resin set available in this scale.
Not sure about the colour. When in normal use, they would be either MSG or "Aluminium and I've seen what appears to be both on the "Mail" Hurricanes.
In the pic posted, the one under the port wing seems to be black, with the starboard probably white, therefore matching the AEAF stripes, which would make sense, as otherwise the tanks could obscure the stripes sufficiently enough to lead to misidentification, the Hurricane at that period not being exactly common.
The drawing below shows the shape of the 44 Imp Gal tank and pylon (not to any scale, enlarged from a smaller drawing).
I'm not sure, but these tanks
may have been adapted as containers for carrying the mail etc - I have the info somewhere, but so far, I can't find it !!!