Yes, it was briefly "repaired" in "Attack of the Cybermen" featuring Colin.  Although he was able to override the police box form, the 6th Doctor still had little control of the results.  They still tended to look conspicuous, like a grand pipe organ when they materialized in Foreman's Scrapyard.  Before it aired, word got out (maybe intentionally as a publicity stunt) and viewers feared the police box would be gone for good.  Of course, by the end of the serial, the Doctor meatphorically said, "Forget this," and the iconic blue box returned.

And that was only 23 years into the program.  No, the police box has become far, FAR too important a "brand recognition" symbol for the show, particular since the lead character changes every few years.  The prop may be replaced every so often and as a result a few details and proportions may get "tweaked", but the overall form will remain.

Sincerely,

Bill

Tempt the Hand of Fate and it'll give you the "finger"!