Is there a way to re-watch the end credit sequence in the 2013 Lego Marvel Superheros game?

I know this is a pretty old game by now, but I've been playing through it with my son recently, and after we beat the final mission the "House Party" mission hasn't unlocked.

I've found some posts about a similar sounding issue, but no clear fix for what to do about it. The most promising candidate is to watch the credits to the end - I think this is most likely as the game actually crashed for us during the final cut scene (due to a smudged/scratched disc).

I've cleaned the disc and installed the game to the Xbox HDD to try and fix this, but our issue now is that replaying the final mission doesn't give the complete final cutscene any more, regardless of whether we play in free play or story mode. I also can't find any menu to rewatch cutscenes from, and Google suggests there isn't one.

I'm pretty sure at this point that we'll have to suck it up and start again, but is there any chance that someone knows how to either force the Stark Tower Deadpool mission to unlock, or how to rewatch the end game credit sequence (on the slim chance that that'll unlock it)?