Rust appearing beneath Hammerite/Kurust...?

[Swift&Bold]

........as for hitting it with a hammer it's not really a conclusive test !!!

Indeed. It's probably just further weakened what was dubious anyway.

 

[jordan1]

Corrosion has has seriously compromised the strength of the area and needs sorting properly IMO.

 

[steveo3002]

cleaned it up well didnt it !

i guess its hard to say about if its gone very thin from a picture , as far as mot goes if they cant push the poker tool through it then its a pass