I'm curious to know why you want to vote in UK elections.
I live in the UK but vote in US Federal elections because: a) I am subject to US tax law regardless of where I live, b) the result of US Federal elections can affect the whole planet, not just the US.
But can the same be said of the UK? If you are living in the US the effect of UK election results would be minimal I would have thought. Unless you are subject to UK tax, then voting makes clear sense.
When I moved to the US in 1999 I went through the hassle of registering to vote in the UK. This involved going to a UK consulate as I didn't know any other BCs living there. When I later moved inside the US I gave up - too much hassle - I had no UK income and didn't live there, so didn't affect my life. Sure, my family was all living in the UK but they had their votes they could use.
To be clear - I'm not criticizing, just interested in understanding - perhaps I overlooked something in my thinking all those years ago when I gave up with it, so would like to understand your thinking here.