L322 Rear speaker vibration/rattle - how do I get to it?

Hi all,
Still getting to know my "new" 2011 RRV Autobiography which is awesome but one really annoying niggle is the vibration/rattle from the rear-most speaker on the passenger side. I thought it was the parcel shelf but it's definitely the speaker (or in that vicinity) and is only present when the speaker is being used (i.e. if you play music just through the front, no issues). So, I'm not particularly mechanical or knowledgeable about cars in that way but can follow instructions and keen to investigate and solve this. Any help or advice much appreciated as I'm not sure where to start ... I had a quick look for screws or anything but they're well hidden I guess. I love my music so this would make my day if I can solve it quickly and easily. Thanks in advance

Answered my own question; took another look at this today and with some gentle pulling, it popped off. Couldn't see anything causing the rattle but having put it back and tested it, seems OK (for now). fingers crossed it was just loose somewhere and is sorted.