Clearly I misunderstood the email BA themselves sent me in december
Dear sigma421,
We wanted to let you know that from 15 December 2025, the price of Reward Flights will increase. This will affect both the Avios and cash elements of the fare.
The extent to which lying, often for no reason is just embedded in their comms culture is really appalling. There was no reason to bring up award pricing but given they put the prices up and communicated it two months ago, why the heck would you?