This is true. The 40th was created just prior to their deployment with the BEF. It was made up of mostly special reservist, as documented in the journal.
When he was called up on August 5th and reported for duty at Newcastle he was assigned to the 39th as acting Quarter Master Sergeant at Borden Camp. When the 40th was created he was transferred into the new battery.
Through my research I wasn't able to find much information about this battery compared to others. Is there a reason for this?