The whole non working IFE issue amuses me,
When I started flying we all watched the same screen. if you didn't like it, tough, Then seat back IFE started rolling out and it frequently failed. On any long haul return trip the system would usually fail at some point.
So you learnt to pack a couple of books to read and maybe some puzzle books and a pen.
The OP was informed at check in that his IFE was not working so had opportunity to purchase a book or some other alternative in the airport. £30 should cover those purchases.