It's just an example of how TV was less sophisticated years ago. You're supposed to just assume and accept that Timelords know a Tardis when they see one, even when it's camouflaged. And can even tell which model.
You can then retro-engineer the whole thing and imagine that Timelords sense objects in spacetime, not just see people and items in 3D, so they sense other Timelords, Tardises and events that are wrong, can be changed or are fixed, etc. A bit like a human may not be able to tell the temperature by sense alone, but you still 'feel' whether it's hot or cold, or if the temperature changes relatively. Even blind people can tell when the sun pops out from behind a cloud because the effects of the sudden bolt of sunshine is felt on the skin.
The Type 32 was recalled due to the brakes randomly locking and the airbags going off for no apparent reason in mid-flight, although it was a very long time before the High Council acknowledged there was a problem. Even then, they stalled until the next financial millennium before rolling out the recall program.
Before finding the Cardiff rift, Eccleston's Doctor used to take the Tardis to Fred Dibnah for periodic servicing and repairs.
