Wrong child page shown

Hi All.
I'm building an events site. There is a global landing page showing all content, and then region specific pages showing local content only.

The structure is like so (using Venues as an example):
Venues on global page - mysite.com/venues
Venues in town 1 - mysite.com/town1/venues
Venues in town 2 - mysite.com/town2/venues

I am duplicating then modifying the pages from the global pages to create the local pages, this means they all have a similar structure, but then I change the content.

My problem is this: if I go to mysite.com/town2/venues I am shown the content for mysite.com/town1/venues. WordPress is not differentiating the pages. If I change the page slug for Venues in town 2, to venues2 it works perfectly.

Am I missing somthing?

Thank you
James