Wow Ralph.
Wow.
Any possible charges against Cog and the Chav?
Ehhhhh probably not. It's not illegal to walk along behind someone in public. Ralph allegedly assaulted Cog first by trying to grab his phone, the first instance of putting Ralph on the ground is self-defense (and basically every other putting him on the ground too since Ralph kept following them).
The extra punches to the face when he's on the ground is dodgy area. If they aren't fighting back, you're MEANT to let them go, but it's easy enough to argue heat of the moment or if Ralph is holding your wrist (like he was with this guy), you might be able to justify it but it's less clean.
The worst bit is when Ralph spat on the dude and the dude actively approached Ralph as he backed up. At that point, it's seen as you're the aggressor in most countries since Ralph was retreating... but because Ralph spat (an assault from a distance), especially something so low class and disgusting, you could probably argue heat of the moment too.
But really, Ralph might get a written warning for grabbing the phone, the friend could potentially get a bit of trouble but it wouldn't be jail time.
If the police haven't arrested Cog and his friend by this point, they aren't getting arrested. Because it's impossible to follow up with foreign nationals, police generally work off a pro-arrest policy for people without a potential bail address to process them quickly. So I doubt the police give two shits about this, especially since Cog's friend can speak Portugese and apparently just shit all over Ralph and the cops let them go. It REALLY doesn't help that Ralph told the police that Cog and his friend had knives and brass knuckles. If the police search you after that and you don't have those, the police generally don't believe your story at all.
TL;DR - The Portugese are used to drunken retarded Britbongs fightings, they literally couldn't give two fucks unless you kill someone.