Yeah, I would second this. I know you guys want to hurry up and get hitched, but she could get stuck here for quite a while. As in many months. I am not convinced the Donald won't throw the borders into a hard lockdown - nobody at all in.
And while she could use the NHS in an emergency, she'll be a paying patient for anything else - assuming they can do anything for her if she gets ill while here. The NHS may be on overload, if the virus thing goes badly. I'm actually not sure she'd be in a better position if she was in the USA at that point, though. Medical care in the USA ain't cheap, and if it goes badly they'll probably be in worse overload there than if she's here relying on the the NHS. Assuming she doesn't have health insurance that covers her over here. It might actually be cheaper to pay cash for care here, if not. Assuming it's needed and available.
But... If she makes it in, I hope you guys have some wonderful times together.
Might be a good time to go out into the countryside and stay somewhere quiet, take lots of long walks, and enjoy the time together. While true love may not really conquer all, it can sure help in a battle.
Let us know if she gets in.