Just a heads up - even if you have been abroad for more than 15 years, you can vote in elections now - but you need to have been previously resident in the UK.
I'm not sure what I think about this tbh. I don't think it really makes sense and it would be better to have an MP who represents overseas voters like some countries do rather than say you have to vote in your last constituency. I'm still pissed off that overseas voters couldn't vote in the Brexit referendum which changed their legal status!