Kin el fellas! should have warned you that the reason the gate is off is due to the rough seas at high tide which actually covers the top of the gate! you guys have been pretty lucky, coz f**k me that waters cold! check the tide table and give an hour either side of high water for it to be accessible level,
incidently where the fan looking thing was should have been directly below the pumping station so there should have been a service cover leading upwards into the pump house! which would've been second option should the salty Blackpool water have been nearer neck level!
