In a fictitious situation we assume a contract completion date of say Week 100 with the Employer willing to take over the works early. We however plan to complete the works at Week 80 with the Employer then obliged under Cl 35.1 to take over the works within 2 weeks with PM certification within a further one week under CL.35.3 (say week 83). At tender we note the Employer requires accommodation and vehicles for the duration of the Contract period, does this mean we allow to Week 100 or, as the plan is for him to take over the works early, would we need to allow for up to say Week 83 only.
Providing there is nothing in the Works Information that says otherwise(that you have to provide it for 100 weeks), you would be entitled to price the 83 weeks rather than the 100 weeks - exactly the same as your own prelims. the risk is yours, as if you over run yourself then you will still incur prelims and still have to provide their accommodation.
I would add as a general observation, this is why it is important to use the right contractual language as it is unclear what the ‘contract period’ is as it is not an NEC term. !