It all depends on the “data date” of the programme, i.e. the date they have rescheduled the programme to. If they have issued the programme on the 11th March but it was for progress up until the data date of the 28th Feb then that is what you should be assessing. At that point in time (i.e. 28th Feb) was that a reasonable forecast of everything they had done up until that date, and a reasonable forecast of everything going forward at the point of the 28th Feb? Anything after that data date will be picked up in the next programme which will be for the period following 28th Feb. You would have to assess against the four reasons of clause 31.3 if there is a reason to reject that programme. Having said that – it is very lazy for them to submit a programme on the 11th March that is not showing the progress and the knock on affect of everything that has happened in the preceding two weeks.
Project Manager can instruct a revised programme at any stage, but the Contractor has the “period of reply” (as stated in CD1) in which to issue the programme.