Can costs be claimed in interim valuations for items the Contractor believes to be a compensation event (as it is currently incurring costs of same) although it has not as yet been confirmed by the PM as a CE and a quotation has not been requested?
This is under option B.
From reading clauses 11.2(21) and 11.2(28) together you can only include in assessments of the Price for Work Done to Date compensation events that have been both implemented and the work completed.
The simple contractual answer is no. Strictly CEs should only be included in the PWDD when the CE has been implemented and the work (relative to the CE) has been completed.