I have a 2.2dt Grand Espace also, and when it was ticking over it made an intemittent noise, which may be the same "growl" as you describe.
I thought at first it was the plastic wheel arch covers or plastic undertrays vibrating, but when these were removed the sound persisted.
When carrying out an oil change, I was allowing the car to tick over, and as I lay underneath I saw the main ancillary drive belt vibrating as it travelled round.
I offered a hammer handle against it and the noise disappeared.
I replaced the belt with a new one and the noise went away for a while.
When it returned I was not pleased.
I mentioned the problem to a local independant Renault mechanic and he assured me that it was the automatic tensioner that was the problem.
If your engine is the same as mine, the automatic tensioner is a large spring covered in a rubber sleeve, which puts tension on an idler pulley just above the main crankshaft pulley.
I examined this spring and could find nothing wrong, so I greased up the bolts it swivels on just in case it was stiff.
This helped for a while but once again the noise came back.
On futher inspection of the spring I could see that it was hitting the aluminium cover which was preventing the spring taking up all the slack in the belt.
I toyed with the idea of filing down the head of the spring to give more clearance, but thought this was a bit drastic, so I thought elt is too long, why not fit a shorter belt", so thats what I have done !
I went along to a local motor factor who looked up the length of the standard belt, and then he found one that was about 7mm shorter.
It was amazing how 7mm on a belt that was nearly a metre long made so much difference.
It took some effort to get it on, but now it is on, and has been for a good 6 months, the noise is no longer.
I have thought about the problem a bit more since then, and I think the root cause could be the excentric pulley at the top rear of the engine that has either worked loose and slipped to its minimum setting, or was incorrectly reset when being refiited after a timing belt change took place.
The correct solution is to reset this excentric pulley, but it seems impossible to access with the engine in the car, so my solution will have to do until the engine is removed at a later date.
I hope this is of some help to you.