Smoothing a wall

[badjohn]

I have an image of a model against a featureless wall.  Well, there is no deliberate or desirable featuring to the wall but there are imperfections and shadowing that I don't like.  I would like to apply some blur to the wall but not the model.  I have tried a few ways but I cannot seem to get it right.  

 

I have creates a duplicate of the background and selected the wall successfully but now I need a mask from the selection so I can hide the model and allow the original unblurred image to show through.  I cannot seem to get it quite right.  Any suggestions?

[DWright]

To create this effect mask the model on the duplicated layer used the selection brush to select the model and then from the Selection click Invert Pixel Selections and this will select everything apart from the model and press delete to remove the background, go back to the background layer and apply the blur live adjustment to it

 

[badjohn]

Thanks, that's the effect that I want but I might need a few more hints.  I am quite new to Affinity and even back the PhotoShop CS3 that I used to use, I have not tried this before.  I have recently managed to apply levels and curves selectively: select the area, create an adjustment layer, and edit the selection (typically but it a bit) but I cannot seem to apply that the procedure to this case.