So here's the scenario: Whilst preparing for a ULH full flight, the ISM informs you that all the PTVs in F class are not working. Having consulted the ground engineers, they advise you that in order to fix the system, it will take about an hour delay past ETD. You inform IOC/ENG via the Company frequency and are told to close the doors and depart.
Swissair 111 was brought down by faulty IFE by the way.
I always try to pass the buck and take some of the weight off of my shoulders when making decisions, if at all possible. As a Captain, in most airlines that I have worked in, you are already responsible for more than enough stuff that you can't control. So why take on more responsibility unnecessarily?
So, I would put the snag in the book. Then it is up to engineering to clear the writeup. If they MEL the system, then so be it. If they fix it, again, so be it. You've covered your rear and safety has not been compromised. You've also avoided making a decision you did not need to make.
And don't feel bad about the engineer, I can guarantee you he will be doing the same when he contacts his supervisor. And he will most likely do the same and contact his boss. It will travel up the chain, until it gets to somebody who is paid to make those decisions. Just as it should.
You don't have the complete picture in this case, why would you stick your neck out and make a decision that could impact down route schedules and maybe cause cancellations? You don't know, maybe they have an IFE specialist contractor at your ULH destination and this aircraft has been rostered specifically for that port - for that reason.
Just my 2c