The British Vote in Local Elections

This is the list for Somos Mojácar in the last election. Since we don't have any idea (because we are not of any importance), it is hard to know whether, following Brexit, those with a Union Flag next to their name will be on the same list in May 2019. That's Jessica, Adele, me, Gid, Keith, Nikky, Mark, Brian and Liam.
In Mojácar, there are some Brits on other party lists too - will there be any in the 2019 elections?
In other towns across the province, some Brits feature in local government, or in the opposition parties, or simply on a party-list. Will they still be there in 2019? The same thing in other provinces as well. The Ministry of the Interior could clear this up in an instant, but, fuggit, why bother?
How many Brits are involved - even peripherally - in local Spanish politics? Will they lose their rights to stand for office? Will British residents in Spain lose their rights to vote?
Does anyone care?