Following John Kennedy’s question about which version of ICOADS was provided at JISAO project, it would appear indeed that this is v2 although they do not say what they are providing.
As a result I have recovered ICOADS v2.5 from KNMI climate explorer and have re-run that analysis.
There are some small but interesting differences in the new version, in particular the war-time period glitch has changed. This will require re-calculaton of the simple adjustment I applied that cannot be done in 5 min.
There are small differences in the FFT that tend to reinforce the points I made rather than change them.
The unfortunate similarity between the HadSST3 adjustment and the variation in the original data still shows the main effect to be removal of the majority of the long term variation from the majority of the climate record (the pre-1970 part). The later warming is given a gentle helping hand.