Thanks Pdreher
I've added some room treatments on the back wall and that has diminished the glare. Tried some on the side walls also, but this caused the bass to reduce substantially and the trebble began irritating again.
I've replaced my Kharma Supreme Ref silver/gold speaker cables with an old pair of Cardas Golden Hexlink 5c from my second system and this has added much needed warmth and made the sound substantially less aggressive and certainly a lot more enjoyable.
However, I honestly feel my system deserves better cables than the 15 yr old Cardas which at times causes a bit of bass booms and also is a tad slow and less articulate.