Last Saturday, I got to attend Shuto Con. It was a lot of fun to meet other Hetalians and I even got to shake hands with DrewRadLad. (I'm a huge fan!) I was cosplaying as my version of Britannia and a lot of people really liked my version. I even got complimented on it by someone known on Tumblr and YouTube as HetaFacts (I recommend her highly.)
This is just so I could explain why I see Britannia the way I do. Keep in mind that the only information I got from the wiki is that she's a Tsundere.
First, there are people who are confused that I see Britannia as Germania's daughter and not his lover. Personally, I could never see them romantically at all. Then, when I learned that it's believed that the people in Britain and the people in Germany have common ancestors, I came up with the idea of making her Germania's child.
This also helped me explain why she has magic (since she's Scandinavia's niece) and why my version has blonde hair.
Instead of England being a bastard child, SHE is a bastard child. She has half brothers. That's why her accent is so different. (I understand that that's not how accents really work, but I'm bending that rule because they're countries.)
I played with the fact that she's a Tsundere a bit. Because her father and uncle were pretty protective of her (as she is the ONLY girl) she never received affection that wasn't from family members. When Celt first flirted with her, she became so flustered that she had to run away.
Another thing is that English is a Germanic language. She used to speak the same language Germania did, before she was forced to live with Rome.
Her attitude towards Rome is very similar to Germania's because that's how she was raised.
I hope this helped explain my view of Britannia, the mother of Scotland, Ireland, Wales and England.