I am sure there will be a lot of European suggestions but I'd pop one in for Whipsnade in the UK (depends if you want to travel here of course) as a really good photography location.
There are quite a lot of collections like Whipsnade where photography works around within distance from London (including London though it is more crowded and 600mm there would be rather too long, I'd say a zoom or smaller prime would suit better there) which might be combined if you wanted to see more things.
Whipsnade wise there's very little glass and a lot of large, expansive enclosures for bear, wolverine, lion, cheetah as well as rhino and ungulates etc where shots work either without a fenceline or through fencing, with opportunities to blur the background and exclude man mades. They also have really good bird shows where she might also get to indulge in BIF (if she is into that).
I would also recommend Yorkshire Wildlife Park for similar reasons, it's an excellent zoo for photos and the Polar Bears in the pool are a treat at 600mm, travel wise it depends how far you want to go. Bears specifically, Bristol is also really good for photography particularly at the long end, but I am not sure I'd travel to just spend time there. If however your daughter also wants to do some wildlife photography and particularly birds there are lots of centres to try that out with wild birds and Bristol and Slimbridge would be good to combine. I frequently spend a whole day at one or two enclosures doing photography at Whipsnade, but I am rather sad and probably not typical. If going to the UK I'd recommend some RSPB / WWT or local trust sites but it depends how much you like bird photography.
There are also hides you can hire, which feed birds and animals (most are ethically run to avoid dependence but worth researching carefully) and that can be super interesting and good for ensuring something 'turns up'.
Edited to add I'd also say Chester is good for photos, lots of places to get good shots without too much in the way and a fine variety of different animal and bird types to practice on including some lovely free roaming spaces. Not sure I'd take my 600mm to Chester though, 400mm or smaller prime or a zoom with a 500-600mm only at the longest end would be my choice.
This is the Whipsnade website
Whipsnade Zoo | A ZSL conservation zoo
And this is the gallery where you can get an idea about the animals and enclosures and some of the opportunities.
ZSL Whipsnade Zoo - ZooChat