Hi gadb, I took the timing belt cover off today and listened with a tube. The noise is 100% coming from the belt, precisely at the point where the belt leaves the camshaft pulley. There are no unusual sounds from any of the pulleys so it seems to be just an idiosyncrasy of the Gates belt. Reassuring for me to know that it's not an issue with the pulleys or water pump.
I only just came across this thread. Somewhere on the forum, and a few years ago - 2018/19? I posted about a very similar noise which our 1.2 2010 Panda 60hp was making. Quite similar to yours except it was there from when we bought it second hand just before that. Compared to yours, the noise from ours sounded more like a tensioner or water pump bearing failing or, maybe, an overtightened timing belt. I mentioned it to the selling garage but he said he'd heard this noise in both small Fiats and the Ford Ka and it is a "characteristic" of the engine. I'd been watching our Panda on his website for a few months before going to view it and he'd dropped the price a couple of times. When I test drove it the brakes made a hell of a racket but I could see it was due to rusty front disks and the salesman, stupidly, let drop to me that he'd given several test drives in the car but noone had bought it. I'm not surprised with the noise it was making - but I am surprised they didn't sort it? - Anyway, I negotiated a big additional discount and bought the car.
Over the next year or so I got stuck into "sorting" the vehicle out, most of which I've made posts about, but one of the first things was to fit a new timing belt kit as the noise was worrying me. (Gates "full" kit which includes the water pump. I've used Gates kits for years and they are my default favourite). I bought the "proper" timing tools for about £40 on ebay and the job went well following Andy Monty's excellent guide and the Haynes manual I'd bought. So it was very disappointing to find that the noise was still there on startup! A systematic investigation of the auxiliary (fan) belt - I'd fitted a new aux belt as I always do when doing a timing belt - it's tensioner bearing and the air con pump pulley bearing all produced no finding, other than that all was well. Running the engine with this belt removed didn't banish the noise either, so it was off with the fan belt and remove the timing belt covers again. I was still convinced it was a bearing, even though the tensioner and water pump were new. I started going round everything with my mechanic's stethoscope - a long screwdriver stuck in your ear gives much the same result - but results were inconclusive. Then I stuck my old "listening tube" in my ear and went round everything again. All quite except when I went near the camshaft pulley. So I carefully, a little bit at a time, moved the end of the tube all around the pulley and it immediately became apparent that it was whenever the end of the tube was hovered over where the belt meshed with the pulley teeth that the noise was loudest. So, looking at the drive belt end of the engine, leaning over the driver side front wing, it's where the belt meets the pulley at around 9 o'clock (if you imagine the clock face markings). I spent quite a while moving the end of the tube around and it was definitely this precise place where the noise was coming from. I then checked the tensioner marks on the tensioner - mine has the automatic, spring loaded tensioner - and they were spot on. It's worth noting that you'll have set these pointers up when the engine is cold so if you're now checking with the engine hot the pointers will appear to show the tensioner slightly over tensioned. This is because the block and head expand with the heat of a hot engine so the centre distance between the camshaft and crankshaft will slightly increase. The auto tensioner can cope with this because it's spring loaded which allows it to maintain the required belt tension whether the engine is hot or cold. If you have the earlier engine with the fixed tensioner then we could have some very interesting conversations about how best to achieve the correct belt tension, however I think you're engine will have the auto tensioner YeYe?
So, I could find absolutely nothing wrong and reinstalled the guards, aux belt, engine mount etc and just started using the vehicle. That was 4, maybe 5, years ago. She's still making the same noise, as she did with the original belt fitted, which annoys me greatly as I'm an obsessive perfectionist, but Mrs J doesn't know what I'm complaining about and can't hear the noise at all. As she's the main driver of the car I suppose that's Ok then? Because of my obsession with this noise I've had Kenny, at my local wee Fiat independent, take a listen and he told me that it's nothing to worry about. Some of them make the noise and others don't, seems to be completely random. You either have one that does or one that doesn't.
Subsequent to this I've tended to listen to Pandas and 500 as I'm out on my daily walks and I do, from time to time, hear one making very similar noises. I think Kenny is right, you either have one which does or one which doesn't! Becky, our Panda, will be needing a new belt this summer (5 years since last one, and I'm going to try a different make than the Gates just to see if it makes any difference to the noise. I'll post the outcome when I do it.