Now BA fares from London Heathrow are priced in a slight premium (see further more down below) Hence the sweet spot would want to maneuver up just a little on the scale. I highly suggest getting the Elite Edition of Scott’s Cheap Flights (now named Likely). I’ve made use of https://businessflightshop.co.uk/blog/how-to-find-the-best-first-class-flight-before-your-next-trip/