if its a car you dont rely in....ie a weekend toy, then get it stripped and welded up, you have had it long enough!
my old ERST failed its mot on a rotton floor pan and chassis legs, so i stripped the interior did all the prep work grinding etc, and then took it to a guy on sandridge lane (recommended by rob) and he did all the welding of new plates. then i jjust painted the inside and undersealed the underneath and put it all back togther
all in all it probably cost me about £250 all in and a few weekends work