As nobody posted a comparison, I thought I would.
So, as stated above, CWL-DOH saw 8,897 passengers in September which is an average of 148.2 or a 58% load factor.
Birmingham to Doha (and established route) saw 10,683 passengers. That's an average of 178.0 per flight or a 70% load factor.
Manchester had 27,356 passengers shared between 60 A350 flights and 17 787-8 flights. I make that out as a load factor of 64%.
Better than Cardiff, but not by a great deal. Let's see how the winter goes.