QBD 10 December 1989. T, management contractors to the DoE, sub-let a Works Package to G. G were entitled to monthly advance payments and the subcontract provided that "when the valuation has been agreed by the SoS, the MC shall certify the same to be paid by way of advance". G claimed an extension of time of 73.5 days, T granted 39. In October 1987 T wrote to G to recover money due because of their failure to complete on time and included a list of set off claims and calculation of liquidated damages leaving G with £496,781. Later T issued a Subcontract Payment Authority No 12 deducting £95,360 for set off and £36,000 for liquidated damages. G agreed that the liquidated damage sum and their extension of time were independent and therefore the subject of arbitration However they claimed the set off payments had been improperly deducted. Despite repeated requests by G for particulars of the set-off claims T had failed to supply them. T claimed they were due to delay and this meant the