I think I’ve figured out where the ambiguity is. If there is overflow to the next page it will clear to SHUTDOWN, if there is no overflow, which is the case for a failure with damage after the TCAS is actioned, it will clear the entire ECAM (or to the next underlined title). It would also be the case that if the TCAS had been left in TA from a previous exercise then there would be no overflow and the entire ECAM will clear as
Server too busy says. So if you’re SOP is to get to the SHUTDOWN box and then CLR ENG 1 FAIL it will bring SHUTDOWN to the top in order to reveal the second page. If your SOP is to just keep going to the bottom of the page then selecting the TCAS to TA clears that line which removes the second page and clearing ENG 1 will clear everything.
The key here is that if there is no overflow, clearing will clear from underline to underline which means you need to ensure all actions for the underlined system have been completed, not just the ones up to the next related failure. This is still doing one procedure at a time, you don’t skip a FAIL item to do a SHUTDOWN item to then go back to a FAIL item.