According to FR24 you'll be flying on G-EUUF. That's currently just past the Channel Islands on its way to LIS. The BA site has it leaving LIS at 18:00 and arriving at LHR at 22:45. That seems an awfully long flight, even with the french ATC restrictions. It's only a 2hr15 flight usually.

I would expect your current departure time to be brought forward unless anything untoward happens.