I think bodge refers more to the temporary works being somewhat rudimentary in appearance since by definition it is not permanent. Presumably a permanent fix will involve planning permission and the like.I've no idea what ""stuff on Twitter" might be or how reliable it is, but installing temporary works should never be a "bodge". It's a specialist discipline in its own right, and is subject to just as much scrutiny of design and installation as permanent works, since lives depend on its adequacy. It just has to be done a lot quicker.
The ground conditions are almost certainly poor since the 1850 bridge kept sinking and there are gravel pits nearby.