Both Nick Adderley and the Dunn-Charles family's spokesman, Radd Seiger, were positive about how the 'clear-the-air' talk went at Wootton Hall Park this morning (Tuesday, December 17).
But the Crown Prosecution Service (CPS) is still yet to make a decision after being handed the file from police weeks ago following the crash near Croughton in August.
Ch Cons Adderley promised: "We will stop at nothing to make sure that justice is done whatever form that takes.
"If that means if we have to go and canvas more forcefully around getting that individual back to this country then that is what we will do."
The relationship between Northamptonshire Police and Harry's family has not always been rosy after the delay in telling them Mrs Sacoolas had left the UK as well as Twitter spats and a war of words with Mr Seiger.
But the spokesman said their moods had visibly lifted by the end of the nearly two-hour meeting with Ch Cons Adderley, in which he apologised to them.
"We moved fairly quickly on to what we can all do in Harry's honour and to build a legacy for him because what the family really want to do is to make sure that this never happens to another family again," he said.
Ch Cons Adderley described the meeting as 'magical' as they have been able to share how they want Harry's memory to live on as well as reconcile the breakdown in communication between police and the family.
Harry's father, step-mother and step-father were at the meeting but his mother Charlotte Charles did not come as she is so distraught at seeing the footage of Mrs Sacoolas driving at her US home.
Mr Seiger said: "She must have a different type of blood coursing through her veins than the rest of us."
Ch Cons Adderley said he is 'confident' extradition will be sought but could not comment on the CPS' deliberations and does not know why it is taking so long.
"I do know that they are working hard, I do know they are looking at all of the consequences should a decision go this way or that way," he said.
"I think what they're trying to do is they are trying to get this positioned so once that charge is laid, they know what they're going to do next."
The family are due to meet Foreign Secretary Dominic Raab today - another potentially frosty affair after calling for him to be unseated during the General Election over his handling of the case.