It would be nice to know what the will says exactly.
Assuming it instructs the executors to sell (as opposed to granting them the power to sell) then (assuming all debts, legacies etc are paid):
1. Must they sell come what may?
2. Can they sell even if all the persons beneficially entitled and being of full age instruct them not to sell but to assent the property to them?
The answer must surely be no in both cases, though I can find no authority to support that position, not that I have looked that hard. However, section 39(2) of the Administration of Estates Act 1925 refers to "the right of any person to require an assent or conveyance to be made" but I can see nothing which say what that right is.