looking good. I looked at one of the cars today, it has about the same amount of rust as yours had. I might cut into it this summer.

 

That's some awesome welding on such thin metal

 

i let the welder know thanks! He put in another layer of sheet metal behind some of the parts but he got it done

 

I've checked mine, and the plate doesn't show any corrosion.
On the other hand, the inside of the storage bin has been affected, but the structure of the whole area is in good health.
I have removed the rust inside the bin, and when the time comes it will be fixed.

 

I have the same issue, about a quarter size bubble. I’m hoping to cut from inside and weld in a patch. I’d hate to attack it from the outside.

I’m just happy mine doesn’t look like OP’s.

 

I had some serious rust and my storage bins are the cleanest part of the car

 

if you can see it on the outside and you want it done right you should do it from the outside imo. Post a pic of it

 

What do you ting of riveting a patch rather than soldering? After all, proper rivets keep airplanes together. I'd be happy to hear it.

I relied on rivets and industrial two comp. epoxy resin to save my Maserati 2.24v when I discovered dreadful corrosion all around A pillar where soldering was pretty much impossible.
A friend working at Boeing suggest me the type and spacing of the rivets; it took me a painstaking precision and hundred of hours of work given the complexity of the task, but the result was excellent IMHO.
Picture of part of the required patches I'm talking about (there's more):

 

I think it could work I’m no expert but I don’t see why it wouldn’t if you figured it all out.

 

This problem is rarely seen on RHD cars with 4 seats. I have never seen an Australian car rust in this spot. I think it's safe to say the problem originates from the storage bin frame. Selection of materials and design was likely poor because the whole storage bin concept was an afterthought. The cars were always 4 seaters domestically and designed that way and for whatever reason they decided to market it as a 2 seater in North America (same as the FC and FD).

 

This is probably why non-USDM cars don't have this rust issue. Seems USDOT hosed us with the addition of the plate.