Interesting, is your Terra level or slightly lop sided? I was under the impression that all Fiat mk1's had the spacer and Seat only removed it on the Marbella to save as much money as they could (like the fixed shut rear windows and the single rear leaf suspension

).
Now come to think of it, my Terra does 'lop side' but to the left.
I thought it was mismatch tyre sizes but is suddenly occurred to me that it used to be left hand drive...
Perhaps it will even up now (actually I have some 4x4 legs to fit on it)