Sounds like you had a lot of fun.The Haigh tailwheel is really good. If its behaving like a shopping trolley when it was unlocked then the castor angle may be wrong. The vertical bolt around which the tailwheel assembly pivots - the axis of that bolt should be off vertical - leaning forward at the top.
We had the same problem with our Laser. Impossible to taxi it in a decent wind. Solution was to reweld the tailwheel assembly to change the castor angle. I'll have to check the exact angle, maybe only 5 or 10 deg from vertical. Totally controllable and easy to taxi in all wind conditions after the change.
PS I can imagine you'd go to jail for calling on the radio that you're riding a nuclear bomb into town.
Regards,
Dave Pilkington