Realistically? Probably none:
1. There's very few holders in Europe;
2. As far as I know none of them are breeding;
3. For current crocodilian holders -why swap (Joe Public wouldn't appreciate the change to a rarer species) or create new enclosures (at not inconsiderable expense) when they've already ticked the "crocodilian box";
4. For non-current holders it's easier to source a less rare species.
There's a very outside chance an enthusiastic small collection might source some but it seems pretty unlikely to me (for the reasons above). I'm not sure if there are holdings in the private sector (but I've never heard them specifically mentioned).
