Bolt replacement to petrol forecourt fuel tank lids

This set of tank lids must have been serviced many times and the bolt threads have become damaged, We were tasked to remove the old bolts and fit new ones.
Due to the age. damage and corrosion of the old bolts they took a bit of removal, some had to be cut off and drilled out.
We then re-tapped the holes to the next metric size up and ground back to fresh steel for weld prep.
We then inserted new stainless steel bolts and tig welded them to the back to seal them in.