Just found my own answer - sort of..

In THIS video, at 38 & 48 seconds, you can see what I mean...

From what I deduce from some drawings the "no window" is a production join.

As for the window blanks they are usually customer options and can be anything from a galley to a toilet on the other side and they blank the hole.:D

Surely, this is because there are no seats behind the blanks. For example, there's a toilet or galley or whatever there.

Not so much the 'blanks', as apart from the ANA with a window in the lav, I understand that, it was where, what Fred C mentioned, the 'Section Join' is that I was asking about... Hate to be on a long haul in that seat!

From Puget Sound ...

The space where there is no window is due to the air con riser ducts coming up from under the aircraft and into the ceiling. You will notice it on all the Boeing aircraft.

Normally I would agree with you Brendon. I had that thought but it is a very long way back for that sort of thing. As the aircon packs are under the centre wing box the risers are normally just fwd of the wing or over the wing. Aircon is ducted forward and aft in the cavity above the ceilings.

As I mentioned before it most likely is a production join.

787 Test Drive
 

Our Crews take 787 for a test drive :)
Posted September 25, 2012


Nearly 70 of our pilots are currently trained to fly the 787, becoming type-rated via classes and simulator sessions. After we took possession on Sunday, some of our pilots are flying the real thing on 787 training flights.

The Sunday through Tuesday flights allow our pilots to fly the aircraft after having completed a comprehensive ground and simulator-based 787 training program. MWH (Moses Lake, Wash.) is hosting most of the training flights. It is an excellent airport for such training due to its long runways and lack of air traffic congestion compared to most major civilian airports. On Friday, our pilots will fly the plane down to IAH.

“Although United’s 787 simulator is very realistic, there’s simply no substitute for being able to fly the aircraft,” said 787 Fleet Standards Manager Captain Dave Lundy.

The training flights are the next step in the extended process of achieving final certification for revenue operations of the 787. As we previously announced, we expect the 787 to enter revenue service on Nov. 4.

Our 787 Arrives At IAH (Video)
 

Our first 787 arrives at IAH
Posted September 28, 2012

Our first Boeing 787 Dreamliner landed at IAH on Friday afternoon as several dozen co-workers stood by the taxiway to cheer on the newest addition to our fleet. Upon arrival, a water cannon salute greeted the 787 to celebrate United becoming the first North American carrier to take delivery of a Dreamliner.

Customer Service Team Leader Debbie McCormick was one of our co-workers who greeted the flight. “This is the most remarkable aircraft. It’s going to do wonders on our international routes,” she said.

Inflight Supervisor Burton Powell said, “I’m very excited and proud to be part of the airline that brought the Dreamliner to the U.S. It shows that we’re trendsetters and that we have the latest and greatest. All other airlines are going to have to follow suit.”

Lead Customer Service Representative Johnny Johnson, a tractor driver on the Aircraft Move Team, said, “This airplane represents our airline as one. This is our common ground. It also makes us the top competitor. We’re not competing with other airlines – they’re going to be competing with us. Not only am I looking forward to flying on it, I’m looking forward to towing it.”

Operating as UA Flight 7708, the 787 took off from Boeing Field in Seattle, with 787 Fleet Standards Manager Captain Dave Lundy and Boeing 787 Assistant Fleet Manager Niels Olufsen behind the controls, completing the journey to IAH in about four hours.

“The 787 is an amazing airplane with unparalleled advances in safety, efficiency and passenger comfort – a level of sophistication beyond that of the Starship Enterprise,” said Dave, who has served in his role for four years. “As exciting as flying the aircraft is, the success of United, Boeing and the FAA working together to bring this aircraft to life has been equally gratifying. My profound thanks to all the dedicated people associated with this project.”

We now begin a month-long training and certification program that includes non-commercial flights to several of our domestic hubs. As we induct the initial aircraft into the fleet, they will be based at IAH and will enter into previously announced domestic service in November and international service in December. We’ve scheduled our inaugural 787 flight to depart IAH for ORD Nov. 4.

This 787 is the first of five Dreamliners we expect to receive in 2012 out of a total of 50 we have on order. The aircraft features 36 seats in United BusinessFirst, 70 seats in United Economy Plus and 113 seats in United Economy.

See Jeff’s Journal for information on the 787's advantages. For more about the Dreamliner, visit the new United 787 site under Our Fleet & Cabins on the Corporate tab. Here, you’ll learn about the 787’s initial routes, customer-friendly features, environmental advantages and more.

Video of the IAH arrival

http://www.youtube.com/watch?v=aaTraY_MWEk

MS

ANA has just released statistice on their B787 Operations, on the anniversary of their first year in service.

- Fuel savings are 21% not 20% as promised by Boeing.

- Load factors are up compared to other aircraft in the fleet.

- Passenger feedback has been excellent.