There were some British flag makers indeed and I will have to check my files to see who they were.

There's another Second National out there that has a British maker's mark on it that our flag grouped discussed a few years ago.

Why a Second National would have a hoist edge marked "Red Ensign," which was a Royal Navy flag typically, is interesting. Maybe the heading was intended for another flag and used for this one instead? At this time, the Royal Navy used red, blue and white ensigns based on the fleet to which the warship was attached (based on who commanded it).

Your theory on this being a flag for a British blockade runner holds a lot of water based on other known Red Ensigns taken from them including one I examined earlier this year that was recently sold at auction.

Greg Biggs