Ria, Labour are passing a law which should protect you in this.
However I did a bit of digging and under the
laws on German citizenship, whilst the UK is still a member of the EU, you may apply for UK citizenship if you have lived here for more than 5 years legally and still retain your German citizenship. It's almost certain that anyone with EU Dual nationality in the UK will be deemed to have had "permission" to do so and will retain that right after the UK leaves the EU. Any other action would cause havoc for tens of thousands of Germans and Germany is not noted for doing that to it's citizens when they legally entered a process.
That may give you an answer to your problem.
As for May? Talking to #1 son he can't stand her. As a Police officer he believes she has said one thing and done another which has damaged the Police service greatly.
May will almost certainly use EU citizens rights as a bargaining point in any future EU discussions. She'd be insane to do otherwise because you can guarantee the EU will do the same. Which tells you what I think of Labour.
We've been offered sponsorship for dual citizenship here in France and if things start going right off the rails we'll take that offer. Although I'll have to go on a crash course in French for at least 6 months to gain enough language and history skills to be accepted.