I would tend to agree about the Arcam/Epos combo. I has Epos M12 and with the wrong SS gear would be bright due to the metal tweeter. This was mentioned in the reviews about them as well. I heard the Arcam, great amp, lively, detailed and basically neutral. Are the ESL tweeters metal?
You may want to try taking the edge off via different cabling. Discovery cables as an idea. Also, give the Cable Company a call, for a small deposit they will let you demo various cables at home. You don't lose your deposit, you can then apply it to a purchase with them.
Good luck,
PS - You could also switch amps to a Creek amp, like the 5350SE (which is what I had). It might be easier to switch speakers though.