I went to Cambridge Police Station where Danse and 2 other Brotherhood characters were, I was helping fight against the ghouls and all of a sudden Danse and the others turned hostile to me, Not sure why but my companion was shooting all over the place and I may of hit one of them with a grenade (amateur), so basically I had to kill them, but now Im unsure if I can join the Brotherhood of Steel??

in a game this big I assume they wouldnt have only 1 option and 1 way of joining a faction...I've heard you can follow a BoS ship to boston airport to join, but not sure if this will still happen since i've killed Danse?

Thanks!

You're going to have to load from an earlier save, and this time make sure you don't hit them. If you kill Danse you may (read: very unlikely) get a chance later to join, but just to be on the safe side you should reload.

Paladin Danse is only kill-able if you become an enemy of the BoS... Meaning, you can't join the BoS for sure now. Sorry mate but you gotta have to reload a previous save.

Absolute ballache! thing is I dont think I have an earlier save which is silly on my part, I just overide everytime. i've played about 15hours since and I didn't think anything of it once I killed him, until I saw someone mention him and say he's how you join. looks like i'm joining The Institute!

At least you've learnt a valuable lesson: make a new save at least every thirty seconds just in case the game decides to go crazy on you.

There's four factions you can side with mate.

game keeps 3 auto saves afaik and you can decide how much time must pass between each. I have them set for every 10m

That's a good thing, I hate being quick saved right into a death trap.

The game autosaves every so often so you must have a save.