Thank you to everyone's response. I really appreciate the interest and time you all have made to give me advice and food for thought. I'm thinking that I will try and gently clean the front of the lens, a small area near the edge, just in case the stains are internal. If they are internal then as Jeremy suggested, it may be a complaint to Synta as to why the spaces between the lens elements were not sealed properly and so contain moisture. I would have thought that the lenses would have been assembled in a dry environment considering the price of the Esprit range. They should be sealed well enough not to allow any moisture entering internally.
I can appreciate condensation forming on the outer surfaces when bringing a cold scope into a warm space but it shouldn't develop within the lens elements. Hopefully, as one suggested, it turns out to be on the front surface, then the saliva on the finger trick will confirm that.
