Failures on aircraft will always occur. What we should all focus on is that a PIC in consultation with his airline made and took a course of action that resulted in safe landing in Manchester. No two incidents are ever likely to be the same. Only those who believe or naive enough to believe that flailures can and will be experienced only as per the QRH or FCOM blame the crew. A pilot who understands and makes a life saving decision is a better assest than one who thinks life in an aircraft will always replicate the manuals to the dot.
There are too many variables.
I do not believe that the decision was based on economics but on the ability of the crew and aircraft to continue the flight safely. BA is great airline. And when I fly with them I know that I am being looked after by some of the best pilots in the world. Some of the posts on this thread show that we have converts to the teaching doctrine that a set of robotic responses to a memorized set of responses to a situation beats common sense and good airmanship. Some recent incidents/accidents illustrate clearly the difference between believers in the QRH/FCOM and those who truly undesrtand the profession of flying.
Finally and most important a safe landing is more important than killing yourself and passengers etc. than killing yourself and others by believing recommendations for machines you may not fully understand will always save your ass.