This is linked with Why did the First Doctor land in a junkyard, and why didn’t the TARDIS disguise itself as junk?
The discussion’s salient points were:
”"The TARDIS had a malfunctioning chameleon circuit, at the time of the debut of the first episode of Doctor Who in 1963 it was common to see Police call Boxes in British Cities. That is why the Tardis disguised itself as a Police box, "answered Jan 7 at 18:39 DoctorWho22
"within the first nanosecond of landing its chameleon circuit analysed the surrounding area, calculated a twelve-dimensional data map of all objects within a thousand-mile radius and then determined which outer shell would best blend in with the environment.”
"thousand mile radius would take in the whole of the UK and most of Europe (as well as a large area of sea)" answered Jan 5 at 14:59 Richard
Well, given 1000 miles it is very unlikely that it would transform into anything specifically British.
However let's say it is an oversight and it is only 100 miles, or even that in a 1000 miles but the immediate surroundings are more important that the farthest ones, and that’s why it would be something specific to the UK.
Given that, and given that the English Phone Box is a cliché, is there a reason, why it is not just that?
Was it just to be a bit original since most would have expected an English box disguise used as a vessel to be a red telephone box?