Rusted and Corrided Metal Mantel in 1940's Council House

[crisevans]

Hi,
I am in process of planning repointing the outside out houses.
They are attached to a 1940s ex council house.
Above the window in of what we use as a laundry is a metal mantel (not sure what the official title is.) The metal mantel is highly corroded.
I do not know what the most appropriate action is. Should the mantel be replaced if so how. Or is painting it with rust treatment the best action.

Any advice and support would be helpful.

[welsh brickie]

If the surrounding brickwork is cracked then replace it, if not then cover it with a plastic trim and silicone