please advise me what is meant by pacing and how to stop the dog doing this,thanks

Its when the legs on one side move forward together, instead of front right and back right moving forward together (if you see what I mean.) A rolling walk rather than a trot. Move the dog a little quicker or increase the length of your stride. You would be better to stop first, or usually the dog will just pace quicker!

Fillis has described pacing to a 't' ....however I find the best way to stop it is to give the dog a jerk to the side when he does it and this will throw him off balance and cause him to breaak into a trot
Archer

Ooh - never tried that! Much better when youre on the first trip round the ring with umpteen others behind you. Thanks! :D

No probs!
Archer