It depends. You will have provisions if the dd or negotiation would take longer than anticipated and hence the timelines can be altered. Further technically imthe heads of agreement is not legally binding as a whole but elements of it can be binding unlike a contract of sale which is binding in it’s entirety. So the Loi or heads of agreement can be shifted as long as both parties are keen to c an outcome. Hence why it is promising that whilst there is a delay it is progressing as there is a will to conclude it. Remember this was not a sales contract but a Loi.