I never expected so many replies, so much good sane advice, and helpfulness. Now I can really perceive that the 'virtual sangha' is for me, living so isolated as I do! Thanks to all of you who have replied.
I must admit that 'all round mindfulness' is a weakness for me (ie 'mindfulness in daily activities), so I am going to make an effort to be more aware, in a relaxed kind of way, of the mind's workings while doing the mundane, often uninspiring activities of life where the mind feels aversion (such as cleaning, dishes etc).
As for doing a sitting, I will resume today. I will not progress beyond dukkha by being fearful. They are just images, and if I maintain strong mindfulness I will not identify with them, should they arise. I need to remember, whether lovely or terrifying, none of them are self. In short, I need to not identify with the contents of my own mind...
I have to remember how Buddha practiced before enlightenment. He had fear in the mind, but he did not run away from it, but rather would not move from his current posture until he had fully dealt with that fear! I feel that 'dealing with (previously subconscious) fears is what I currently need to do in my practice. I'm going to try to be more brave. Let em come (the mind's disturbing images), I'm ready!