I just meant the TARDIS interior really...

...I don't see the Doctor "fixing" the chameleon circuit, to manifest the exterior as anything other than the resemblance of a Police Box variation, anytime soon ;-)

It's considered an iconic form, even by the Doctor himself, as I recall...

I always inferred the implication (and I don't know if this is backed up anywhere in canon or other storylines) that alongside the chameleon circuit function, the TARDIS was deploying a "perception filter" of some sort, anyway...

I suspect the Doctor will regenerate to a different gender or ethnithity before the TARDIS changes it exterior (more consistently) to anything other than the Ol' Blue Box...

In terms of the interior... the word I've heard is that the current interior is likely to remain for at least part of the next series. But, I guess we'll see...