Painstaking prep work but worth it in the end!
A few products to share with us on that one
Masonry filler: Lime based patching mortar, compatible with the original render substrate.
Window repairs: Repair care system but traditional linseed putty to glazing bars (customers request).
Masonry Paint: Silicate based masonry - Keim Paints do a good one.
Windows: Zinsser Coverstain plus 2 x coats Sikkens AZ gloss.