any help would be great, on PS4 the slog quest sends me to Faneuil Hall but I've cleared it, although it never had a map marker, and it won't progress

Is the quest active in the pipboy? there may be an enemy lurking in there you missed. Did you clear it before getting the quest? (in which case the enemies will have respawned).

Yes active and i had previously cleared this area doing the grasshopper quest. What is happening is I am not getting the map marker showing me to go to Faneuil Hall but that is where the quest is sending me.

Go there turn the quest on and off in the pipboy and see if the marker updates its self. All else fails after a week(in-game) the quest will fail without any real consequence.

thank you for trying to help, I've done all of that and pretty sure it's been over a week in game too, I don't know if the Slog becomes a settlement as I can't progress past this mission, I was hoping that the patch would fix the issue but it hasn't

The Slog does become a settlement.

This is a known bug though. I received a different loyalty quest for The Slog (clearing the super mutants at Breakheart Banks), and didn't have any issues.

Hopefully there will be a fix for this at some point.

Scroll down to the 'bugs' section -

http://fallout.wikia.com/wiki/The_Slog:_Greenskins