e.g. https://beta.musicbrainz.org/search?query=london+AND+NOT+type%3A%28artist+release-group+release+recording+work+label%29&type=annotation&limit=25&method=advanced should find https://beta.musicbrainz.org/area/f03d09b3-39dc-4083-afd6-159e3f0d462f

Looking at https://bitbucket.org/metabrainz/search-server/src/28a3af9a4a61af014a494432bab92b3166f58134/index/src/main/java/org/musicbrainz/search/index/AnnotationIndex.java?at=master#cl-54 it seems to be missing area, place, instrument and series.