Window leak below frame?

[DarkDogZA]

Hi All

Hoping for some advice from from the more knowledgeable folk. I am in an old Edwardian newly refurbed house that seems to have developed a leak after the recent rains. The leak in the picture below is just below a sash window frame.



The outside of the frame looks like the picture below and my current thought is whether this is the source of the issue.



Additional outside view. Wooden board below the frame.



Any thoughts / feedback would be much appreciated.

 

[Burnerman]

I would guess you are bang on there.....I'd be raking out the grot below the frame, and getting some silicone in there.
Attend to the sides too if there are gaps.
John

 

[DarkDogZA]

Cheers John, much appreciated. Any preference for a brand of silicone?

 

[Burnerman]

I go for Dow Corning stuff......industry leaders! The 791 should suit you fine.....between £6 and £7 at Screwfix, Wickes or wherever.
John

 

[DarkDogZA]

Cheers!