I run but can't keep up with my wife when she's walking, so I can't speak from my own experience on walking shoes, but, subject to that caveat, here's my opinion:
Try Nike Pegasus runners - they'll cost about €100. They provide great cushioning. If you have issues with (ankle/knee) stability, you may be better off with Assics. My wife - walks about 5 miles a day, probably a mile or 2 shy of your jaunt, kmelvin, - used to wear walking shoes - generic type - and was always complaining. I finally convinced her to change to pegasus - no more complaints.
btw, if your runners get wet or damp, stuff them with crumpled up newspaper immediately you take them off - or they'll smell like cat's p*#s