Dr. Beachcombing at his folklore and history blog recounts the day Donald Omand tried to exorcise Loch Ness of any evil spirits. You can read it here.
The Doctor asked for and got some photographs of the event, but I can go one further and have found a video of the exorcism episode from the 1976 documentary "The Legend of the Loch". The bloke holding the bottle of water for Donald Omand is Ted Holiday himself. I believe this was actually a rerun of the ceremony as the BBC was not there for the initial run.Click here for the link.