The War at Sea

Small problem with timing...Nelson and the Victory reached England after the chase to the West Indies on August 18th. The watch could not possibly have been made between then and August 20th, when it is said to have been presented. The Victory had been away from Britain for two years, so if the officers had clubbed together to commission the watch, they would have had to have sent their instructions (and the money) to the watchmaker from the Mediterranean many months earlier. Is there any documentation for such a possibility?