Kentish Brickfields

Mr Ron Fairman, author of The Crouch Valley Parishes has written requesting information about the supply of stock bricks in or about 1888 by barge from Halstow to The Stoke Farm Landing at Althorne in Essex on the River Crouch for use on the Southminster Branch Line. The old stations have now been demolished and he has in his possession bricks marked "V WH 6 SB" (or SO)". If anybody has information as to which Kentish Brickfield they came from he would be most grateful.