Hello Steve, we did one a month or two ago. I don't believe we changed the sprockets but we did buy the special tool to lock the camshafts. A word of warning (speaking from experience) when you remove the cover you will see a short shaft with three oil rings on it (they look like small plastic piston rings). If they happen to be split (as one on ours was) it will fall off as you remove the cover & in our case cause a over advanced camshaft fault. Best to replace them.