Ok.
Big milestone hit on the weekend. I welded up the rot, ground it down and then liberally applied some brush on seam sealer. I didn't go for pretty, I went for rust prevention. This won't be a show car but it won't see gravel or snow either. Wet days are still an option but we'll see - I might just drive it like it should be driven.
That's in he future.
For now, the brush on seam sealer is in all the right places, the rot has been converted to a phosphate, the ingress areas have been painted with rust paint now as well. I've really tried to stop the rot, but you always miss one little spot and I'm trying desperately to minimise this. It literally is like trying to cure cancer - hence the comparisons.
So, once the paint has cured for a week in the 1C-6C cold with the occasional blast of heat when I'm in the garage, I'll spray the undercoat on with the shutz gun, then paint it again...
As you can see, it's been gooped on and the undercoat will hide some of the brush marks etc. It should look like most restos in a week!