Ahhh, but I have a cunning plan Gary - please let me know what you think...
0 - cut out section of outer sill to provide access to the whole jack bracket area (done)
1 - drill out jack tube middle attachment to floor with (my large) spot weld cutter.
2 - slot the sheet metal immediately ahead of the bead weld inside the car, as shown.
3 - remove the jack tube outer bracket, and with/then the jack tube (with help of chisel if necessary).
4 - check the integrity of the metalwork around the tube with borescope and cut and TIG in new sections if needed.
4 - file the end of the new tube to fit snug against the old weld bead + trim the slot as needed to weld through it.
5 - hold the new tube and bracket into final positions.
6 - MIG weld the end of the new jack tube to the old weld bead (and close the slot at the same time).
7 - plug weld the middle of the tube to the floor, as per original.
8 - attach new jack tube outer bracket.
9 - TIG new metal in flush to the outer sill section that was removed to gain access.
10 - stand back and look really smug.
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