The removal and boarding up of ancient windows took place over much of the country, even in rural towns, particularly where airfields, military, naval or places of strategic importance existed. Many were of mediaeval origin. Interestingly work was done or continued during WW2 in some large abbeys, churches and other buildings, in order that the skills of those artisans familiar with cosmati floors, (egg) tempera paintings and other highly skilled crafts, was not lost. After all it seemed unlikely that such people - unless they wished to do so - would be of great service doing other war work. Even whilst the war raged, once the bombing had abated, those in officialdom were making plans for a post-war future. For instance, much of post war Birmingham planning was done in mid to late WW2.
Incidentally, whilst Coventry Cathedral was destroyed by bombing nearby Lichfield was not. The Luftwaffe used Lichfield as a marker due to unusual spires. Ancient churches, usually aligned east/west, were - and presumably still are - great for compass bearings by aviators.