Great song, Ogi...
Not to pick nits, but Northern Soul referred to the type of music played in Northern Soul clubs in the northern and mid-land regions of England. Not where the song was recorded, and almost never a ballad.
To be classified as Northern Soul it pretty much had to be sufficiently up-tempo for the type of dancing universally done by the patrons of those clubs.
In the early days, at least, mainstream popular songs from Motown, etc. were far less popular in the clubs than rarities that British DJ's would discover on trips to the U.S., scouring though obscure label warehouses and cut-out bins in U.S. regional used record shops.
The Northern Soul dance style does not seem to have evolved since the 1960's up to the resurgence of the clubs in England today.
As it happened, a lot of the labels that produced that music were located in the northern U.S., and more complexly orchestrated than the usual style of music that came out of southern labels such as Stax and Hi, etc.
I have to admit that when I was first exposed to this music I thought it meant music produced in the northern U.S. vs. the southern U.S. as well...
The issue is quite complex. Here is a Wiki article about Northern Soul that goes into a great amount of detail. A long read:
Northern soul - Wikipedia