JDoc, Thanks for your response. I do intend to go back soon and look at this with structure scan to see if it shows anything. I'll post a follow up once I get there.
It is a silt bottom with very few boulders or features across the loch. I've yet to play around with the settings as this was the first time I'd used it and I could hardly believe my eyes when the screen lit up. Its funny how you begin to doubt everything you think you know when starting over with new equipment. I am surprised at the number of fish that seem to be in this loch.