Stephen Adams wrote:
I find that when I'm trying to perform a technique if I try to concentrate on my centre my either my footwork suffers or my arms flap around.
Move your body from your hips. Make sure you close your armpits (wakishimete) and have your hand in front of you while your arms are extended in te-gatana. It's simply said and really hard to do.
As a beginer, take the time to do the technique right rather than fast. Fast happens as you just let your body do the work without your brain interfering.