Bad 4.6 block?

What are the symptoms of a slipped cylinder liner with out taking the heads off….and once the heads are off…is it obvious or do you need to take measurements to tell? I thought the engine in my 04 disco may have had a bad head gasket…simply enough to fix. And because of a couple other issues, I was going to pull it to repair. However, I just need to know how to tell if the liners are ok. From other threads, it seems to be the consensus that there is no point in trying to repair a block with slipped liners.

Any help would be great!