have they had or did they have

[Over the top]

Which one is correct
Have they had/Did they have a car when they were living in London?
and why?
Thanks

 

[euncu]

***Neither a teacher nor a native-speaker***

From "they were", it'd be correct to say that they are not living in London anymore. So, since you are asking about a finished period of time, it should be "Did they..."