Conservatory is leaking through an old knot in the wood

[Moge]

The walls of the conservatory are wood, and everything is otherwise water tight, but there is a leak through a know in the wood as you can see in the photos I've attached.

On the outside the knot has mostly rotted away and it is soft an spongy to the touch. This is the view from the inside.

My question is: what's the best way for me to fix this myself? Do I need to fill the depression left by the rotted-away knot on the outside with something? Pack it full of silicone?

Any bright ideas would be appreciated.

Thanks!

View media item 50498 View media item 50499

 

[foxhole]

Cut out rotten timber and fill with two part wood filler.

 

[Moge]

Thank you, foxhole.

Is chiselling it out and maybe using a rasp to finish it off my best bet for removal do you think?

 

[foxhole]

A p180e is the ideal tool but wood chisel will do.