Under an NEC3 Option A contract, the Contractor notifies a Compensation Event and the PM’s decision is that the Prices are to be changed and instructs him to submit a quotation.
After the quotation is submitted, it becomes apparent that the work covered by the CE is no longer required.
How is the submitted quotation dealt with in this case?
If you have instructed something and a quote is provided and acceptable, then you implement it.
If you then instruct that back out again, that’s a new CE. I don’t expect that if the first one was +£10k this one will be -£10k, though. You also can’t ‘reclaim’ any movement of the Completion Date.
If the Contractor has just found a way around the issue (i.e. designed it out), that’s their good luck.