Had anyone had similar situation ? 

I would imagine that leaking sunroof would cause water in the boot?

Is this coming from A/C evaporator in the boot ?

 

Is that sunroof the fixed or opening type? Opening sunroofs have rain drainage channels or pipes which can become blocked.

It is panoramic and the first part opens up

I have never done this, but if you look at recent forum topics other folk have flushed their channels successfully with warm water. One fellow even used drain cleaner, though the corrosion risk would be too great for my liking.

Here's a funny one - I thought I had somehow lost a bottle of water in the back of the car - searches never found it and it was only in the recent cold weather that I realised the water is inside the rear tailgate!  Removed the two bungs from the underside and litres of water came out!  Spoke to the main dealer and they booked it in for water ingress without even a murmer.  Seems like this is something they already know about as they said it would need to be booked in for a week!  This is a 2023 SQ7!