The ad I saw for the 110£ case clearly stated " PU Leather".
You may have seen a different ad than the one I saw, then. Not to be picky, but it said:
GDK LEATHER PU SHOTGUN CASE, WOOD,LEATHER CASE,26-32"GUN CASE,FELT LINING 165pu
.........not PU Leather.
The above was copied directly from the ad itself. If PU means polyurethane, what does the 165pu mean in reference to the felt lining? This is why I question that it is in reference to polyurethane. Does it mean the felt is also polyurethane? I'd think not, which is why I speculate that the PU has another possible meaning.
I will message the contact person at GDK and ask him straight out.