Listening Room or Components or my ears?

See an audiologist first, if you want to avoid or postpone a wild goose chase.

My suspicion is that the Focal speakers are the biggest culprits for your treble character. 

There are so many ways to remedy this but I will attempt to give you the easiest vs the most comprehensive solution.

As others have recommended, getting panels on your first reflection points may help with this issue.  I would recommend gik acoustics or doing a DIY panel build.  Not hard.  Just need some stiff insulation and fabric and frame.

Another thing you can do is get a Umik-1 and use room eq wizard and see what your frequency response looks like both on var smoothing and at 1/6 smoothing.  You may be able to determine where that resonant frequency is and use a notch EQ filter to reduce that band.

And if you really want to go spend some money, yes maybe it's the focals.  I recommend tektons for detail without glare or harshness.  Double impacts are my go to recommendation under 5k

I was a long time in this hobby before I realised the importance of the listening room and then more by accident than design.

A visiting distributor commented on how good my listening room's acoustics were,It is my 21x12 ft lounge with a concrete floor, coved ceiling and large leather three piece suite.

The speakers, now Hailey Reference 2,2s are on one of the long walls about halfway and firing across the room, but at the time of his visit were Kipod Signature passives.

So I endorse other members comments on reviewing the listening room set  up.I am not that familiar with Focal speakers but in my limited experience they can be a bit treble dominant

Start with the room first though before changing the Focals

Couple of thoughts from a fellow Focal owner:

Are the cables fully run-in?

Your speakers are very close together and this may be strangling the midrange thus highlighting the HF which you aren't loving.

My mains are a little more than 8' apart.  Experiment with toe-in and rake which will change how the HF arrives at your position.  Typically, Focal's need very little toe-in.

Perhaps find a way to temporarily hang a blanket on the front wall behind your mains and see if this improves things.  Good luck and cheers.