"However, it seems to us that since the decision in Polkey it is necessary for a Tribunal when calculating the amount to be awarded for compensation to ask itself this two-stage question: if the proper procedure had taken place, would it have resulted in an offer of employment? This was the question to which the Tribunal did address themselves in the earlier hearing, and to which they gave the answer that it might have done so. What the Tribunal failed to do, and what in our view they should have done, was to go on to consider first what that employment would have been, and second what wage would have been paid in respect of it."