Water spitting from exhaust

The saga continues.... I just took it for an even longer run than this morning, and the water spitting seemed to stop by the time I got back home. So maybe the water coming out was just the normal for a cold start (although it did seem a bit much earlier).

I checked the coolant water reservoir and that seems about normal and there doesn't appear to be any creamy substance in the reservoir or oil filler cap.
I did dip my finger in the coolant reservoir and the water did seem a bit greasy, but I'm guessing this is just because of the anti-freeze??

During my test drive, I switched off the engine and the exhaust noise (which I mentioned in my original post) is still present. The noise is only present when the car is moving.

I'm now wondering if it has anything at all to do with the engine/exhaust, but maybe something else.

It definately sounds like exhaust noise, as if the exhaust were leaking. But I've checked it quite thoroughly and all seems OK. And then again, when I switched off the engine during my test run (as mentioned above), if it were an exhaust problem, then surely the noise would have stopped???

Any sugegstions would be greatly appreciated.
Thanks
Paul