Port of London Authority (PLA) Hydrographic Service was commissioned by DONG Energy Power (UK) Ltd to undertake repeat multibeam echosounder (MBES) and side scan sonar (SSS) geophysical surveys at the Gunfleet Sands 1 and 2 offshore wind farm in the Thames Estuary. The scope included surveying a 100m-wide corridor along the export cable route between the offshore substation and the landfall east of Clacton-on-Sea, plus MBES surveys around and between selected turbines (A6 to F6) and assessment of scour around the substation, with associated analysis such as difference surface charts and volume calculations.