Possible Clues:

• Horse's one of five in eastern Spain
• Zebra, for example
• Dancing Queen cover single describes those going off the rails perhaps
• Affected queen goes around island - it concerns the nags!
• What might be characteristic of an Arab?
• Kit out inadequately-covered Geordie mare?
• Zebra, for example, is one of five in Eastern Spain
• Mustang, for one
• Prima donna and I have an interest in the horse
• Like a horse, one of five appearing during mid-week