Repair or scrap / break

I don't have any diagrams for you but my understanding is that the body bolts are held captive in a kind of double skin box type structure that I think is unavailable as a separate part possibly and needs to be custom repaired/replaced. I've not done it myself this is only what I have read in here.

These posts ( after a search on rust) suggest that we might have to approach the repair by cutting a hole through the floor from above

My Jimny so far, from Rust heap to less rusty heap...

Another green laser build  and a later  Page

Ulysses

Suzuki Jimny Falconer Edition

Project Rust Bucket

Re:My 01 Jimny, another Norwegian

Rust protection

Not quite the Jimny you have, but a previous generation although the concept is the same.

First the top inside layer is removed
 
Then a hole is opened up to reveal the mount

 

Then plating is added
 
 

Then the hole is patched up

And the original top panel is fitted back
 
   

And then its gone!

Thanks Martin

Well the two rear body mounts are now repaired ( welding skill bought in) and the car is MoT’d.  But, I still have a running problem.  As indicated previously, the CAT was supposedly blocked and was replaced.  The car ran much better after that but perhaps not quite back to full power.  On a trip out a couple of days ago it seemingly went well until we hit a steeper hill on the dual carriageway whereupon the power dropped off and I had to change down a gear or two, with lorry’s very close behind me.  

The car had been a bit fumey after the cat replacement so we took it back and asked the garage to check the joints.  They said that they put paste on the joint while it was running but it was blowing back as they put it on, suggesting that there was further blockage downstream, perhaps at the back box.  Today it was noted by sniffing near the tailpipe that the exhaust has a funny smell.  

So, it definitely has at least one and possibly two separate problems.  To note is that the spark plugs are probably very old.  It runs at normal temperature, at least on the water side.  The car is now over 25 but has done 52,000 miles.  Any suggestions on the lack of power and smelly exhaust.  

Its probably worth noting that that wire mesh "crush collar" that sits in the flexible joint on the exhaust is often way too small on aftermarket exhausts and it blows at the joint pretty quickly after the exhaust is re-assembled.