Last summer on our first outing I had a similar problem to a, (I had connected properly), arriving at Black Horse Farm around dusk I could not get any power to operate inside the caravan. Early next morning in daylight I unscrewed the electrical power unit and slid it out of the housing to find that the connector which resembles an electric kettle plug and socket had become unplugged from the back of the power unit. When I pushed it back in and reconnected the lead into the site tower socket all was well. It made me think though that this lead must have been loose since the caravan was new, four years ago, it was such a tight fit into the socket that there was no way it could have worked loose itself.