The highest rank they obtained, at least as far as I am aware, was Wing Commander. - Chugalug
That is rather sad for many reasons in view of their outstanding war service, and provides an interesting, and perhaps equally sad, contrast with the post war career of Rear Admiral Józef Bartosik CB DSC, as will readily be seen by reading between the lines in both
Rear-Admiral Joe Bartosik - Telegraph
https://en.wikipedia.org/wiki/J%C3%B3zef_Bartosik
The reference in the latter to Commander (later Captain) Mike Henry in which the then Captain Bartosik is quoted as saying 'that he considered Henry unsuitable for an important submarine appointment "understood to be impending"' is of special interest since the appointment concerned was as Commanding Officer of HMS RESOLUTION (Port Crew), the first Royal Navy Polaris submarine, and subsequently as Captain of the 10th Submarine Squadron, consisting of the four SSBNs.
Jack