Its so old no one can agree on how to flue it, let alone categorise it!
Speak for yourself. I know exactly how ot should be done. I also understand the "procedure", and it does not involve lying to justify condemning a boiler, a tactic often claimed to be employed.
I will say, however, that I cannot find my post immediately after the hole was brought to attention. I may have said it may cause this to be elevated from NCS to AR. I meant ID. I think that if a call was placed to Gas Safe that they would say that you cannot effectively "repair" it, although a few bands of silver tape probably would. All my NCS comments are based on the liner being sound, and the appliance passing the tests.
I have come across many flue liners in lofts, used to connect the transition block to a roof terminal. Obviously wrong, but I checked with GS (or maybe Corgi), and the advice was as expected. NCS assuming etc...
A lot of those I visited were to fit a fire, but all of those were upgraded, or the job declined.