I think it's the other way round, isn't it? So far, anyway.
I've no idea how far it will fall, after the end of 2020. But that has no bearing on whether it will fall or not. Which said, my best guess is parity or a bit worse, maybe 90 cents to the pound, in about June; things should be more stable by then.
All those currency traders are trading at that price now, and they will adjust their pricings as time goes on. As they do, all the time; because that is how they make their money. What they trade at now has no bearing on the price in January.