Wow four and half months to get back to the flying field to test the modifications to the plane
. Thats what happens with a new born baby in the house.
Weather was a bit windy on the weekend but I had a window of opportunity from family responsibilities and off I went.
Take-off was still all over the runway but once in the air everything was predictable and clean looking. Landings were fine - no more slow speed rolls.
Therefore safe to conclude that the loose covering on the aileron was the issue and has been now been resolved.
Regarding the ground handling when taxiing at a fast idle the plane would travel straight - so landing gear not the problem
Increasing the throttle sees the plane drifting to the left (as expected?) but attempts to correct withe right rudder even at 50% expo the plane would over correct and the zig zags started.
I have no problems with the ground handling on my extra so I didn't think it is all down to poor technique.
Took the plane home and checked down thrust - 1 degree, right thrust - 1.75 degrees. rudder throws - ah.
The standard throws for rudder are low rate - 3/4" high rate - 1.5". Mine was set up with low rate 1.5" high rate 2".
I reduced the low rate throw to 3/4" and hope that will now enable more picturesque take offs.
Thanks to all for their assistance and suggestions.