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Can anyone help me with this:

Ive set up a directory, however the homepage theme doesnt seem to narrow the entries down correctly – as per screen shot….

what am i doing wrong or not set up right? im getting listings show that are way to far away from the postcode thats been entered and also – getting an area show up thats no where near the country im in?????
Ive tried using google and Mapbox as the map listing as well