Sort search results by distance

I’ve had a website developed on our behalf which has gone live today. While being test-driven, it has become apparent that when searching for an activity in the “activity search”, the results that come back are not sorted by distance from the search location.

I have asked the company who developed the website to add this feature, however I have been told that this cannot be done. I find this quite hard to believe given the frequency this feature is used on numerous websites.

Can anybody clarify whether this automatic “sort by distance” feature can be used on an activity finder in WordPress, and if so what the steps are to do so?

EXAMPLE – http://activetogether.org.uk/timetable/

Thanks,