Thanks for the advice jim_0068. I tried your drill and it seems my right arm is having a bad effect on my plane line. With just my left arm i swing down plane quite nicely hovever as soon as i put that right arm on the club my first move at start down is too under and across getting the club shaft pointing well outside the target line. I think from there i can't release properly which is why i don't get any finish swivel.
Can anybody give me advice on getting that right arm to work for me and not against me?