Thanks for your replies.

My kids are both aged under 12 so really shouldn't be separated from us. And I agree with the sentiment that if you pay for seating there should be systems in place to prevent this sort of thing happening. I live in the SW of England so inevitably fly with EZY a lot of out of BRS and have never have any paid seating moved with them - sadly feels like a bit of a gamble with BA. Anyway, like fdem has said, it's likely we won't be flying as I suspect many cancelled flights owing to quarantine on the Swiss side.

May wait it out for a week or so and see what happens.