NEC ECC: Can a Client choose a specific make from a list of specified materials in construction stage?

Can Client specify at this stage what materials we have to use?

if the Works Information contains a list of specified materials that the Contractor can select from and the Employer is now restricting this list to only one choice then the Project Manager would have to change the Works Information which would be a compensation event. This would entitle the Contractor to assess the difference in cost between the now specified material and what he could have chosen from the wider list. The assessment should also consider any change in the risk profile and any effect/potential effect on the programme.