However, I'd like the opinions of the good people on this forum as to how bad the corrosion is, and what needs doing. Very difficult to tell from just photos I know, but I've included plenty (to get brownie points off Metalmick8y

The MOT garage use a mobile welder that they speak very highly of, and his opinion is that I can patch these areas. I'm inclined to prefer replacement inner and outer sills, although the inner sill seems fairly good apart from a previous repair near the jacking point as you can see in the last few photos.
So give it to me straight - what needs doing to do this properly?
The interior photo below is from when I had the interior out earlier in the year, and I was pleased at the time that it looked to be in pretty good shape (the rusty colour inside the side panel is waxoyl overspray):

Outer sill (seems reasonably solid except where the hole is, and apart from the scabby join along the bottom edge):






Suspension mounting (bit of a hole):


Inner sill/rear jacking point (signs of a previous repair, but not noticeably weak forward of this point):


