Of course.
The obligation only exists if the prosecutor in the U.K. is aware of that information. As you rightly say, in many cases they won't be because the requesting state has to provide [Technical difficulty—Editor] evidence or a very limited amount of evidence. The obligation can only arise if they are [Technical difficulty—Editor] something in the course of acting for the requesting state that does undermine the evidence that they've already been given and have put forward to the court.