Ride faster
Good advice. I can add that you will probably feel less need to flail (c.q. find it easier to ride with hands behind your back), when you ride fast. The reason is that every steering correction is more effective at speed.
Thanks guys a few things to try. Trying to sort out my legs and foot position at the moment.
Have moved my seat up a touch to enable me sit up straight. Think its feeling better.
Should I be moving my seat up/down when changing the position of my pedals?
Do you mean on dual hole cranks? Definitely! Your leg should be almost fully extended (but comfortable) when the pedal is on the 6 o’clock position. Whenever you move saddle up or down you have to change the pedal position and vice versa.