“Whenever the discretion to grant an amendment is invoked, the Tribunal should take into account all the circumstances and should balance the injustice and hardship of allowing the amendment against the injustice and hardship of refusing it.”
“Thus the reason why it is ‘essential’ that a tribunal consider whether the fresh claim in question is in time is simply that that is a factor – albeit an important and potentially decisive one – in the exercise of the discretion.”