Thanks for the replies!
Jonathan - yes and this was the amazing part!
Just go with your instincts! Sure there was quite a bit of turning to soon, too late or not at all but on the whole, it was good. If you close your eyes, after a minute or two, all your other senses become more alive. There is a large part of timing that is handled by the ears (rustle of gi, feet on the mat etc..) but these are no good if you do not harmonise properly by relaxing your breathing and trying to 'feel' the attacker. This was equally important for the tanto-dori, obviously.
On reflection, there was another benefit to the exercise and that was it has now made me see that there is a certain unity to all Aikido principles. The movement without being able to see yourself means that the hip is more in your mind. At least for me!
I am loathe to say such a thing due to the starwars and mystical allusions, but the thing is not to anticipate. "Don't think - feel" as Old Ben Kenobi would say. ahem. It is true though, the anticipation ruins your awarness.
I think O Sensei once said something along the lines of "Do every technique as if for the first time and the last time." This, I suppose can be interpereting in many ways but for me, doing a technique as if it was the first time is to not anticipate too much. Don't have pre-conceptions about the technique or the attack otherwise if something changes then you are lost. As for doing like the last time, I feel that it is telling us to remain calm as whatever happens will happen. Both fundamental to awase I think.
Jeez I ramble on - I will have to restrict my posts from now on!
I am going to try some ken kata in the dark / with my eyes closed at the end of next lesson and see how my awarness of my own body changes.