Yeah, I would just use a 2x4, or whatever I could fit (I am not a builder or structural engineer). My main worry would be about pulling those bricks down, but if that's a bit of steel running under them as a sort of lintel (would be mad if there wasn't something) then I would be less concerned.
Yeah it is, doesn't seem to be the strongest of things but it does across the whole width of the chimney breast taking support from the vertical bits at the side.
Yeah, I would just use a 2x4, or whatever I could fit (I am not a builder or structural engineer). My main worry would be about pulling those bricks down, but if that's a bit of steel running under them as a sort of lintel (would be mad if there wasn't something) then I would be less concerned.