Window - Water Ingress

I wonder if anyone could give me any clues as to where this water would be coming from on my upstairs bay window?

I had the issue before the bay window was replaced 2 years ago, and slowly but surely the water stains have appeared again. So it looks like a small amount of water is coming in from somewhere. I would have said the window originally but as it was there before and after replacement it makes me think it is more likely the bay window roof, or the bay window tile face.

If anyone with more experience could give me a few clues I will turn to the window fitter or get a roofer in to look at the bay window flat roof or tiled front.

Please see attached pictures.

Thanks,
Martin.

Looks like condensation judging by the mold under the window.Cause - lack of adequate ventilation.

Moldy silicone at the sill and window join too, as well condensation along the bottom of the glass. Defo a cold spot though for the moist air to be attracted to it, the barrel is only a single skin too looking at the depth of the window sill, that'll be studwork infilled with crudely laid bricks or just plain studwork with no insulation, hung tiles outside over bitumen felt, inside probably lathe and plaster and that's all, no insulation. Be worth and exploratory hole somewhere to have a look

There is a large water stain on the left hand side of the plaster under the furthest left window pain, this is where I would guess water is getting in? There is too much of a stain in one concentrated area for that to be condensation for me.

The mold on the silicone could be due to condensation I suppose, but there are also drip marks under the window sil where as I don't really see any water on the window sil itself to suggest it is running down.

But honest have no idea, I am just saying what I see.

Martin Quinn said:

There is a large water stain on the left hand side of the plaster under the furthest left window pain, this is where I would guess water is getting in? There is too much of a stain in one concentrated area for that to be condensation for me.

The mold on the silicone could be due to condensation I suppose, but there are also drip marks under the window sil where as I don't really see any water on the window sil itself to suggest it is running down.

But honest have no idea, I am just saying what I see.

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Most of the condensation will occur overnight while you are sleeping, so you may not see it.

Never hurts to get up and check both the roof and the sealant around the window but it is quite probably condensation due to being a cold un-insulated stud wall as others have said