Mrs L has a useful question for me (and similar friends!) which is "what would a normal person do?"
Have you asked the MOT man for a quote to get the welding done? If they don't do it in house they'd have a "go-to patcher". Our every day car is a 1987 Mercedes 300TE that "went under the knife" just today. "The art" in our case is to set the standard low, its not a show car, nobody is going to be looking under and asking "those the original floors".
Just a thought before you break this one you know like and trust and take on another with who knows what niggles needing sorting. We're an extreme case in the "love the one you're with" stakes, had this one since before my youngest was born and she's 14 next week. 247,000 on it.