I've not had a great deal of time today, please feel free to add any links to this post and I will update it with any other news later :)
I haven't seen many video's up yet, but here's the one from the MTV Geek short interview yesterday. Thanks to Aylass84
Short round up of spoilers I have caught on twitter:
*Three years will have past since the end of series 4, during which time Morgana has been held captive somewhere and is after revenge.
*Tony Head will be making a guest appearance as Uther (presumably flashback?) but it looks like no Santiago Cabrera back as Lancelot.
*I think we already knew this one...Merlin will have a romance this year.
New poster, showing Gwen as Queen, and Arthur without Excalibur. As it's been seen being used in filming so far I'm assume that this is an error rather than him going back to a normal sword.