Eroding brickwork above bathroom window

[puri]

Please see attachments, I am seeking advice on the kind of job and amount of work involved, e.g. large, medium, small job, I need to specify and best options for repairing this window frame, for instance, is it a simple matter of chasing out the damaged brickwork and replacing with new bricks or something else like installing lintel?

Thanks

 

[noseall]

It looks like infill - i.e. the window fitters couldn't be arsed with the arch, so they slapped some bricks up there instead. It may look better if the masonry was removed and replaced with a similar (window) coloured infill cap, backed up with a membrane detail and insulation.

 

[Ivor Windybottom]

It looks quite old, it was probably originally built on top of a wooden frame, which would have been capable of supporting it. Then someone's blindly replaced wood with plastic, with a gap above, so it was clinging to the edges and resting on nothing, and there you go.

A new window frame with an arched top would be a more expensive but much nicer solution, depending on how much interior work would result and how visible it is externally.