Can anyone advise how to remove the small peep from this sight? I purchased one recently because their advertisement states that the small peep can be removed for CQC shooters but there are no instructions included with the sight & I certainly do not want to damage the item. TIA.

Looks to me that between the screwdriver slot on the RHS of the sight, and the knurled knob on the Left, its a matter of removing the windage screw entirely from the sight base, removing the small peep, and reassembling. The small peep rides on the windage screw, between the ears of the large appeture (spelling?), and removing it wouldn't have any affect on the function on the balance of the sight. If it were mine, I'd start with a screwdriver in the slot on the RHS and would bet that's key to disassembling the whole thing. I didn't go any further than a visual inspection of mine.  Also, my model is the ARMS40L with no reference to the "SP" as noted in your posting so that may be a game changer that I don't know about.

Thanks skipsan. Here's a link to the manufacturer's web site ref the sight I purchased (from Operations Parts). There'a also a 40L P developed by Crane IIRC.

40L SP

Looks like mine except mine doesn't have the "SP" stamped  on it.  

A closer look revealed that the windage knob on the LHS is attached to the threaded windage rod with a roll pin. A 1/16" pin punch would drift that pin out and I believe allow removal of the windage knob.  The screw slot on the RHS of the pin would permit further assembly of the sight and removal of the small peep.

I thought about it
but left mine as is