Not usually a crown with the LLH. LLH was the mark of Lochet Habran of Jurille, Belgium. I've seen it frequently on Ithacas, but I've also seen it on Fox barrels marked Chromox.
There are two different tube suppliers that had the crown over a D mark, Didiere barrel works of St Etienne, France, and Delacour of Belgium. One has rounded lobes to the crown and the other pointed. Hopefully Dr. Drew will be along to tell us which is which.
This HE-Grade being shown is marked exactly like my 1923 vintage big 32-inch XE-Grade 1-weight boomer is marked, crown over D over 1. My 1937 vintage SPE-Grade Skeet & Upland Game Gun has the crown over D over 3.
Another tube makers mark that is seen on all makes is S.B.&Co., Sanderson Brothers & Company. The information I have says that this company started in Sheffield, England, and set up a steel smelting plant in Syracuse, New York, sometime around the turn of the century, and that Lefever used a lot of their steel. Eventually became part of Crucible Steel.
Seems odd that these barrels of the gun in question don't have the "Barrels Not Guaranteed - See Tag" or the Fox Proof mark?!? Here are some more normal HE-Grade barrel flats --
