Somewhere their was a wish that BA has an accelerate Avios programme where you can buy 1, 2 up to 3x the miles earnedd last month. Today I learned that Flying Blue has a similar system but up to 16x. I accelerates my 250 miles up to 4000. The cost was 64 €. I am not sure if it’s good or bad but at least you have a choice. Hopefully AY will adopt this system as well. Likely the BA way.