On the (BBC) radio news earlier only the 90% figure was mentioned, not the 70%. This differs from the BBC news website, which started with the 70% figure and mentioned the 90% afterwards.

Maybe. But it's also time to compete and current headlines are not working. If the public opinion is that it's far less effective then the other 2, what is happening now, you are putting the politicians in a difficult position that want to buy your vaccine. If you dig deeper you will find results for all vaccins are pretty similar. For instance even though one of the trials with Oxford vaccine had more people with Covid sypmtoms they had no severe cases, compared to one severe case with the Pfizer trial. And the total for both are too low to make definite conclusions.