Newcastle has always been 6 flights Mon-Fri with 4 on Saturdays and 5 on Sundays.
I tweeted the airport about the reductions over the summer and they acknowledged the recent reductions and said they are trying to get a stable schedule from BA and working with them.
The extra 7th flight in the past winter season was a slot sitter for the cancelled Doha flights in December and January, it resulted in two flights departing within 5 minutes of each other.
If the route was doing that amazing they wouldn’t be cancelling flights in the height of summer to help fund other destinations.