Genuine answer: none (not being a marine surveyor myself). However, were shingle to be being removed from the Western end of the beach (and deposited where?), then DHB would be obliged as the CHA to inform mariners of the tidal flow(s) involved.
To the extent that the piling may have deflected the "jetstream", this they have done - see NTM 54/17:
http://www.doverport.co.uk/operations/notices-to-mariners/ but I suggest that any such deflection is more likely to be away from the beach.