Postcode brings up wrong country!

You can invesigate what's going on using the web interface for the search engine at https://nominatim.openstreetmap.org

Searching for "NR32 4BF" turns up the road in Australia, because it has an old_ref of "NR32". https://nominatim.openstreetmap.org/details.php?place_id=167374628 . I think this is because nominatim doesn't recognise the exact postcode - is it new? - and so it tries to find other objects that match either the first or second half of the postcode.

Using the "reverse search" on the same site allows you to find the Aspire Centre and check what nominatim thinks the postcode for that is. https://nominatim.openstreetmap.org/details.php?place_id=164924374 shows nominatim has computed the postcode as "NR32 4HE". Perhaps the source of the post codes for nominatim is old, or has some inaccuracies.

If you want a deeper dive into how Nominatim works, and how it chooses the search results, then have a look at http://nominatim.org/release-docs/latest/ . Otherwise I would suggest adding the postcode to the correct building.

If you know the postcode of a house or building it is simple to map. Using iD pick "area" draw the building outline easy with bing harder without. Choose house or building for the polygon you have drawn. Add the postcode. Save it.

To search and find an item it needs to be mapped. I tired a few postcodes, my own, that i mapped and some business ones from a magazine, they work if mapped. I guess the one you found means something in Australia but is not mapped yet in the UK. The solution is for us to map any that we know, especially if it is a new build . I seem to remember that the GB postcodes were something that the Royal Mail owned and couldn't be copied in total. More info. https://wikileaks.org/wiki/UK_government_database_of_all_1,841,177_post_codes_together_with_precise_geographic_coordinates_and_other_information,_8_Jul_2009