What does NEC4 clause 60.1(2) mean?

Clause 60.1(2) deals with late access. The event is that the Client does not allow access to and use of each part of the Site by the later of two dates: the access date for that part, which the Contract Data states, and the date for access shown on the Accepted Programme. The word later matters. If the Accepted Programme shows the Contractor needing a part of the Site after its access date, the Client is not in default until the programme date passes, so a Contractor that programmes access later than the Contract Data allows has moved its own entitlement back. To establish the event the Contractor shows which part of the Site is concerned, the access date the Contract Data gives it, the date for access on the Accepted Programme as it stood, the later of the two, and evidence that access and use were not allowed on that date. A part that can be entered but not used is still within it. The Contractor notifies the event under clause 61.3 within eight weeks of becoming aware that it has happened, normally the day the date passes without access. The change to the Prices is assessed under clause 63.1 as the effect on the actual Defined Cost of work done by the date of the notification and the forecast Defined Cost of work not yet done, plus the Fee, usually standing people and Equipment, remobilisation and out of sequence working. What most often goes wrong is that the Accepted Programme has not been updated, so the date relied on comes from a programme the Project Manager never accepted, or that the event is notified when the cost is known rather than when access was refused. Any delay to the Completion Date is assessed separately under clause 63 by the programming expert.