I have a window frame and one corner has a small piece of wood rot.
I suspect also that gloss was applied over gloss as this is all peeling.

I am going to use ronseal wood rot liquid in the rot area and then fill with
an exterior filler.
Once I sand down the rest of the wood should I give some sort of
preservative coat first before undercoating/painting? Could I use the
ronseal wood rot for this?

Any thoughts on undercoat & gloss paint regarding makes, I will probably buy
from the local screwfix.

thanks