Some more from Wikipedia:
https://en.wikipedia.org/wiki/Convoy_de_la_VictoriaIn addition, the British authorities in Gibraltar and Tangier were hostile to the Republic. The British oil companies in Gibraltar refused to sell fuel to the Republican navy. The Tangier International Commission denied the use of the harbor to the Republican Navy, because this was contrary to the city's neutrality, but nevertheless authorized the passage of food, goods and gasoline for the German transport planes to Spanish Morocco
This seems to explain Franco's reticence to join forces with Hitler during WW2. DRZW Volume 2 notes that Franco secretly concluded an economic agreement with Britain during the summer of 1940, providing his country with supplies that Germany could never match. DRZW Volume 1 notes that Franco resisted Hitler's efforts to incorporate Spain into a larger area European economy during the war.
Franco owed a debt to Hitler, but he also owed a debt to the British. This article notes that Churchill lavishly bestowed bribes on high ranking Spanish officials during the war: https://www.theguardian.com/books/2011/ ... day-review
So it seems like a lot of "What If" scenarios that involve Franco joining Germany are less plausible than they would seem based on popular literature claiming Franco was pro-German. Britain and Franco had a favorable relationship before WW2, and this relationship grew stronger during the war. Franco never had any intention of joining Germany in a war against Britain.