Either is possible.
If Michael said to the first question "Yes, I went for a week in 2007" then "Where did you go?" would be more natural.
The "Where have you been" also carries the idea that future touring in England is likely.
I'm actually puzzling over prepositions. I was in London and Newcastle. I've been to London and Newcastle.
I think, given that she asked "Where have you been?" that "to" would be a more natural preposition.
Student or Learner