Maybe the seat was supposed to be like that... When we flew LHR > BKK in J a few weeks ago, the leg rest did not extend on my wife's seat. I pointed this out to the FA who told me that, no, it was my seat that was broken by extending! She was convinced that the leg rest should not extend. This was on one of the old 747s so she could hardly use the excuse that it was a new plane and she wasn't familiar with the features.