Gaps, wheel arches and bolt holes all have to be carefully considered to ensure I don't mess this up.
First job is to prepare the inner sill that is going to be covered for evermore (hopefully! Not doing all this again in a hurry) by painting it in a couple of coats of black chassis paint to protect it from the rust.
Then I drilled all the weld holes in the outer sill, took it back to bare metal and sprayed the edges with weld-through primer to protect the join from rust. I applied a couple of coats of chassis paint to the inner section, as shown below.
Next I presented the outer sill to the inner sill and sprayed a little primer through the holes to highlight the welding line.
This was then stripped back to bare metal and sprayed with weld-through primer.
The gaps and arches all look good, including the two ends of the outer sill which I was relieved to see ends perfectly in-line with footwell end and the rear bulk head. Must have done something right! In case you are wondering why the blue wing, the guy I bought the MG Midget off included it in the price as the old one was too far gone.
Next post will be welding in the sill and then on to the A and B post repairs and fitting the door.