Rusted Beading

[emilyvt]

After having water coming into our dining room from the chimney we have the whole wall stripped back down to the brick work. It has dried out and we are ready to start on the repairs. We have since noticed that around our window in the dining room signs of damp around the window. We are getting a new window fitted and we have been reccommended to strip all the plaster off around the window. The beading is completely rusted but I am unable to see any signs of water. Is removing and replacing the rusted beading something I can do myself or am I best to get a trades person in? I am confident in some DIY things but this feels above me. Created this account in the hope I can get some advice and direction on where I need to go next. Our window guy used a moisture meter and the wall was reading as dry but where the blinds are is reading very high and down the sides as shown in the picture.  Thank you!! Thank you!! 

Edited October 15, 2023 by emilyvt
Spelling error

[Mr Punter]

The window head looks damp.  Is there a trickle vent at the top of the window?  If not, install one as you need proper ventilation.

 

Line the window reveal (top and sides) with insulated plasterboard.

 

Look outside and make sure that no water can get into the wall.

[emilyvt]

That is really helpful. Thank you! I will make sure to ask if one can be fitted on the new windows as we have nothing like that currently. 
 

Appreciate your advice!! 
 

Any suggestions on the rusted beading? Thanks again! 

[Mr Punter]

Remove the bead and if there is still any damp, replace with stainless steel, otherwise just new galv one.