There appears to be only one DE1 postcode missing from OSM and it is DE1 1NA that was created recently https://osm.mathmos.net/addresses/pc-stats/DE/DE1/1/
I can't see this postcode on any open source, on RaggedRed or on Nominatim but have seen it mentioned as being here on the less open Streetcheck https://www.streetcheck.co.uk/postcode/de11na
No Crown Park businesses mention this postcode yet as DE1 1LY gets used for Parcel Terrace
If anyone can find an acceptable source pointing DE1 1NA to Crown Park or to anywhere else in Derby can OSM be updated please.