I have ended up re doing the Shed ceiling from the rain water leak.
I replaced ceiling with 18mm plywood and felt on top.
Mistake I did is, I nailed the overlap of felt with Clout nails that is 25mm so it actually pierced through the 18mm plywood and popping in to the shed ceiling.
Is there any suggestions as to will rain water come through those nail holes? And is there any suggestions as to if it is a mistake I nailed 25mm and what actions could I take?