Hi Kev, it's a known issue
see here. We are working on an update to fix this, it's in beta test now. The ios7 release has delayed it going out as-is as we wanted to try and cater for ios5,6 and 7 in one app. Shouldn't be too long now.
To avoid the launching issue you can use the "New Posts" tab on the app, opening items in here will not launch safari.
Sorry for the inconvenience.
Dan