Same problem here
I have the same problem, as a temp fix used four large self tapping screws and washers to tighten the housing up. I do have a new housing but after looking at the amount of work needed dropping the gear lever out I elected to wait until I overhaul the rear suspension in a few months time then do all the underside jobs at the same time. Used the car for a few weeks with this temp repair with out any issues.
One thing to bear in mind is that if the linkage on the gearbox is stiff this may well have caused the issue at the gear lever due to the extra force needed to change gear. I found the gearbox linkage just about seized - there's a few threads on the forum concerning this.