Greyhound Racing Descriptions

You are correct in your guess about 480m being the length of the race. As for A4 or other classifications, it is the grade of the race.

Specifically A4 refers to a middle grade race. This is a UK grading system and the system is described below:

U.K. - Top Grade - (A1 - A3) equilavent to American greyhound grades (A, B) and Australian grades (1, 2). Some 'top graders' may also compete in major race events and can average speeds around a track between 38-39 mph.

U.K. - Middle Grade - (A4 - A6) equilavent to American grades (C, D) and Australian grades (3, 3/4, 4). Occasionally 'graded runners' competing at the very best "city tracks" maybe the equal of 'A1' graded dogs running at perhaps lesser tracks. These hounds average speeds between 37-38 miles per hour.

U.K. - Low Grade - (A7 - A11) equilavent to American grades (E, F and Maidens) and Aussie grades (4/5, 5 and Maidens). Most dogs will begin or finish their racing careers in the lower grades and generally record speeds between 35-37 mph.

U.K. - B Grade - (B1 - B6) This grade prefix usually indicates to either a slightly shorter or longer middle-distance.

As for the OR classification, that means "open race" meaning it is the highest level of racing in the UK. This does not mean that it is open to any participant.

When it comes to the "S" vs "A", this distinguishes the race distance. "S" is for a hound that has qualified in a sprint distance. "A" is for a hound that has qualified in a middle distance. There is also "D" for long distance, "H" for hurdles, and "N" for novice.

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Basically, the lower the number of next to the letter is, the faster the race is. The letter distinguishes the race type (distance) and the distance is of course the actual distance of the race.

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Here are a few references:

Race Guide

Grading Rules