Channel frequency range not balanced

Thanks very much,yes I will swap the cartridge leads,if this points to the cartridge i will use fine shims to hear if azimuth adjustment is the solution.

Hi, well if anyone who kindly answered is still following, I performed another full channel swop from top to bottom, except that this time I swopped the cartridge channels as suggested here.
Without doubt it is my left speaker that is at fault. However an unexpected benefit came about when I replaced the cartridge wires in their correct order. Suddenly the soundstage `sharpened` up for lack of a better description. The stage became more focused, slightly narrower but more specific. 
Good old vinyl!
I have a pair of demo Monitor Audio SE200`s on hold for the near future, looking forward to that.

True, following my previous attempts to locate the problem I firstly suspected the speaker then later ruled that solution out, although that was months ago. At that stage one of my tweeters had blown so I had disconnected the other.
On the advent of upgrading my speakers for the first time in thirty years, I again thought to source the problem.  Untilyesterday I was convinced that the speakers were balanced.
As for the improvement in the soundstage after reconnecting the cartridge I have no idea, I will play a couple of sides again tonight. I also realaigned and serviced my turntable during the tests, which I believe is important every few months.