Possible Clues:

• Equine identifier
• Mark left by an ungulate animal
• Run off after local dance or that's the impression the Arabian made
• Vacuum brand / No longer published (... between letters 2 and 3 ...)
• Impression created by bay?
• Evidence hack, say, was there to find clue — nothing concerning promotion in it
• Dance on the paper and get horsey type to leave
• Hurry off initially for pint, working to make an impression at Ascot
• Support for the devil in the paper leaves beastly mark breaking new ground
• Mark left by rhino perhaps involved tip of horn