i've read/heard that there are residents of islands off the coast of NC with accents similar to what may be found in the british isles. almost scottish IMO.
both the isles and the united states have areas and regional dialects diverse enough that it's possible an outside observer might confuse the two, or think they sound similar. there's no one english or british accent...same for the US.
very early american settlers probably sounded a lot like their brit overlords (in general) before enough generations passed to differentiate them. still, the quintessential "british accent" of then was probably a lot different than the one we love now.
i've seen videos of you singing. your inflection doesn't remind me of anything i'd call british, but you certainly don't sound californian.
languages are always changing. some linguists have found evidence of an emerging southern california dialect....
Yes, Tangier Island in Virginia is the same way. But I'm from the Mainland... I don't honestly think accents come across as much in singing, unless someone is purposely affecting their voice, like some of the modern country singers tend to do.