Autograph Letter, signature and significant part of date missing

Commissioner (Office of the Master General of the Ordnance). Duncombe is instructing a Mr Sherborne of the Tower of London to go to Chatham, Gravesend and Woolwich to see "how many gunnes are mounted & of w[ha]t nature". He expects a report the following morning. The barbarian who cut the signature off also cut off the date, but this letter could well predate the Dutch raid up the Thames Estuary in June 1667 which particularly affected the fleet at Chatham, and indicate preparations.