I think that nowadays only Falcon, Graham Audio and Stirling Broadcast are making LS3/5a speakers.
As far as I know, the Harbeth is based in but not quite an LS3/5a.
.
In my opinion and experience the performance potential of this kind of cute little speaker is too limited for listening to music, namely in regards to dynamic abilities and bass extension. They were designed to monitor broadcast vocals in small booths and mobile studios (Ford Transit), not music.
In spite of the large following, it's just another one of those audio myths...