Only one of these has a clear date. I will attempt to guess the year of the other two. The first cover is from 1941 and bears 3.40 pesos worth of postage. The 2.50 pesos airmail (the highest value of that small series) is rare on cover. The cover was censored upon receipt in England. This cover was posted before the US entry into the war in late 1941, hence no US censorship markings.
The second cover does have US censorship tape, and I will guess it is from 1942-3 from the blue background of the 2 pesos stamps. Also, it bears a 20cLC, and this stamp was first issued in 1942. I can barely make out a 2 for 1942 or a 3 for 1943 from the postmark.
The third cover has combined censorship (US and British). In trying to read the date off the postmark, I can see a 1 for 41 or a 3 for 43... I will pass on this one.
