Your 7 day free trial is measured using days, not hours.
The first day of your trial counts as the full day of your signup, no matter what time of day it was.
Nobody likes an unexpected charge, but fortunately it's easy to cancel if you decide BritBox isn't for you.
To avoid being charged, you'll need to cancel at least 24 hours before your free trial ends, and uninstalling any app you've downloaded won't automatically cancel you. Find out how to cancel your subscription.