So, I need a one G25 clamp without plastic screw. Maybe someony got their G25 selling for parts? I'd buy that clamp. Price depends on you.
Searching ebay didn't give any results.

If you have a broken clamp then superglue it together, drill a small pilot hole down through the clamp and screw in a long No 8 wood screw. If you countersink the hole then the screw head will disappear and wont get in the way when replacing the clamp back into the housing.

I don't have it, simply don't. That's why I am looking for a replace.

Got it. No more needed.