Jus bought a 2009 Jaguar X type and it makes an odd whirring sound when travelling fast, someone said it could be wheel arch fan, but not sure any ideas?

 

I am not sure what they are referring to as wheel arch fan. If the noise is louder at higher speeds I would have the wheel bearings checked for excess play. You lift the wheel off of the ground and grasp it at the top and bottom and try to rock it. If it moves then the wheel bearing needs to be replaced.