We've all of us tried to do our best for poverty-stricken charities.
If you're taking a pragmatic approach, Kurnal don't compromise with intumescent paper - unless you're quite happy that it won't stay undamaged for long. I've done enough building surveys where fire doors have been "upgraded" using intumescent paper where the paper (which to my mind has the same consistency as blotting paper) has become scored or torn in very short order.
You might be surprised to know that the extruded chipboard cored doors you are so dubious about give a surprisingly good fire resistance - certainly better than you might expect from 25mm diameter holes in the middle of a 44mm thick construction.
Don't you think you are treading on dodgy ground replacing old hinges with modern, thinner 'equivalents'?
Yes, I agree that the hinges more likely than not need replacing, but hinges do need to be of a certain thickness and blade width to be able to carry the relevant weight of a door. Many of the problems we see on site are caused by someone going out and picking up a cheap hinge because it looks about the right size (and the price is right). As you can lead a horse to water, so can you lead a client to a responsible choice of hardware but...... doesn't mean he/she will use it.
Couldn't agree more about the need to balance out preservation of heritage with the need to offer some form of fire protection. And you're right - prediction of fire performance is best left to those with crystal balls.