vibration coming from n/s front wheel (for the love of god help me)?

ive got an astra mk4 convertable and its picked up a vibration on the n/s front wheel, ive had a look and i cant see anything wrong!! the wheel still has its weights, theres no play in the wish bone or drive shaft in fact theres no play anywhere really. ive checked the brakes for rubbing and there is none.
so now im out of ideas is there anyone to help me out there???? all ideas welcome!!