Mine was going to be welded in place, but i opted for a new box.
Glad i did because it'd snapped in 3 places. 2 of which you couldnt see where it was.
And out of about 9 garages. Only 1 would attempt it, reason being the masses of wires where it was.
Did you have the new box welded before it was fitted? If not your likely to have the same problem occur again.