Quick answer

Yes to the first, no to the second: a signature on a daywork sheet records only that the hours and materials were employed on that operation, not that they will be paid, so the work may be paid elsewhere, but once daywork payment is established and the sheet signed a quantity surveyor cannot reduce the hours as excessive, as Clusky v Chamberlain shows

Yes to the first, no to the second. A signature on a daywork sheet records only that the hours and materials were employed on the described operation, not that they will be paid, because the work may be paid for elsewhere in the contract; so an architect or engineer can sign a daywork sheet, whether or not it is marked for record purposes only, and still decline to certify it for payment. Once daywork payment is established and the sheet signed, however, a quantity surveyor cannot reduce the hours as excessive; if the hours were wrong the signature should not have been given. JCT 2011, clause 5.7, values daywork by the incorporated Definition of Prime Cost of Daywork and gives the quantity surveyor no role in altering signed hours, and the ICE Editions are to the same effect. In Clusky v Chamberlain the Court of Appeal held that the lower court had been wrong to go behind timesheets that were never said to be fake, and that there was no entitlement to argue the workmen had not worked as expeditiously as they might.