Is an off the shelf ANG catnic lintel that can support uniform distribution of up to 7kN of weight enough to support a stone head going in above French doors? I bought one so our builder can use it with a stone head to replace the failing reinforced concrete head that’s there at the moment, and the outer leaf above it, but now I’m doubting if it’s enough. The doors sit in a 1800mm gap and the lintel and stone head are 2100mm. It’s a two storey 1970s build.