Imposition of milestones within NEC Option C

I'm with you, Neil.

The definition of a Key date is something like (don't have the docs with me) "the date by a which the stated work is to meet a certain condition"

So this instruction is either introducing a new Key Date, changing an existing Key date, or (if client will take over this portion of the works early) utilising x5 to introduce a new sectional completion.

All of the above would seem to come under Cl 63.9, as you suggest.

NEC contracts more than most require quick and co-operative contract adminsitration from both sides, and keeping a good working relationship is really really important to this. I think Damian is right to suggest a sit down with the client to explain your position and understand his, but if all else fails I think you're on sound contractual ground.

Tricky one Neil

I can only suggest you sit down with the client and explain the situation. It sounds like they are under the pump from their client.

There are all sorts of issues which need to be addressed including your revised target cost, have they agreed this?