Not-so-brotherly Brothers

So I've been itching to draw lately but with all the things that are currently going on, I was only able to dig up an old sketch. At least I got to draw my fave brothers...

Except I believe there was a time when these three didn't necessarily regard each other as brothers. I know, I know, the idea of seeing all the British Isles countries being together from the beginning and being this really close-knit family... it's an attractive image. I will admit that I myself really liked that concept. But over the years of studying their individual history, I've started to wonder when they could've all regarded each other as siblings.
England and Wales aren't difficult to figure out, if we go with the idea that England started out as a Celtic Briton like Wales. I can see them regarding each other as brothers quite early on and they could have been pretty close. However we have to consider the fact that they both lived at opposite ends of the island. Meaning, they may as well have had neighbouring "brothers" that they were closer to? Or at least they would have interacted with them more. Wales' and England's closeness does exist though, with them I can imagine them being close brothers early on.

The problem is with Scotland. Scotland was from the north of the island. He did not share the same origins as England and Wales. He was a Gael (Picto-Gael in the later years) and just because he was a Celtic speaker, it did not mean he got along with the Britons of the south. After the Romans left Great Britain, they essentially left the Britons declawed. Generations of being under control of the Romans had led Britons to forget how to properly fight and with the riches that some Romanized Britons had, they were the perfect targets for raiders. Gaels from the north and Ireland, Picts from the north, all these raiders began travelling southwards and raiding the Britons.

Scotland most likely was among those raiders when he would have first met Wales and England. In other words, it is doubtful that at this point Scotland would have been a brother for Wales and England. As far as England and Wales were concerned, Scotland was a wild and vicious raider from the north, interested only in material goods and enslaving people. Not a friend, and sure as hell not a brother.
When did they regard each other as brothers? Hmm, that's not entirely clear to me yet. All I can say for sure that Scotland started out as an unwelcome stranger for Wales and England. (and to England, a possible "brother killer" to boot, but that's a headcanon for another day)