I have recently been caled out to look at a stair window in poor condition with a view toward its restoration. It is in relatively poor condition with many broken pieces, and especially a completely missing portrait at the bottom. This is currently protected by a piece of yellowing perspex over the outside.
The ground of the window is of grissaille in the form of stylised sunflowers. This was a common theme in 1870's Glasgow and brought back through trade with the far east and especially with Japan where it also was a recurring theme.
So although this is a highly painted window, most of it is of relatively simple painting. The main skilled effort in the painting is to recreate the missing head (probably a woman looking toward the man. He appears to be in a Tudor style costume, so the woman must be in similar dress and historically correct hair style. The additional difficulty is to do the modern painting in a way that mimics the existing corrosion of paint on the existing head. There also is a requirement to recreate the sunburst at the head of the window, with doves flying across.
Of course, being on a curved staircase and being over 2.5 metres tall, this presents some problems in removing the four panels of which it is comprised.
The estimate is in and now it is time to wait until the decision is made on who is to conduct the restoration.