British Airways is offering a new promotion when you buy avios through their site.
The promotion runs until April 11, 2021. The purchase limit has been reset and you can buy up to 300'000 for 3601€ with the 50% bonus.
50% is usually the highest bonus available to buy avios at BA. If you are in need of a few avios for your redemption you could definetly buy at this price.