From work on my parents garden post-removal of an air-raid shelter, once you get the glass and mortar out as far as poss I found that (small) brick fragments go away quite quickly with frost.composite roof might be more of a problem - glass-reinforced? Asbestos?

I was finding glass in that soil for years though... None of it stopped me feeding a family of 4 for veg almost completely. I-d buried a lot of composted stuff and turf though, so the composted green waste plan is good!