After the initial design had gained the interest of my cat, I felt it was only sensible to refine the design and correct the problems with the MK1 prototype.
The Laser Toy MK2 still uses an Arduino Uno, but now uses a standard 180 degree Servo for horizontal rotation and the same 180 degree Micro Servo for vertical rotation. The Arduino code has now been expanded with a longer and more varied routine based on Lily the cat’s (apparent) preference.
The movement of the Laser Toy is now far smoother and far quieter, which makes it far more appropriate for a cat to play with!