Man Tony, for a self-confessed Anglophobe you sure to love parliamentary sovereignty.
Isn't that not quite the same thing? I thought parliamentary sovereignty was just that parliament could overrule the courts, not that the courts could not, as an initial matter and before being overruled, countermand parliament.
Anyway, more on-topic, I find it surprising that the Civil Code specifically references marriage being between opposite sexes in language dating from the 1800s. I can't think of another example going back further than the past 50-60 years.