Yep. All outdoor small reptile enclosures in the UK are netted to keep out birds and rodents, which would be a serious problem. Many years ago, vandals cut off the netting of Marwell's outdoor sand lizard pen and they were all killed by rats.
Never had an issue with Rats at all, the wires are to prevent Seagulls from entering the enclosure
The Green Lizards wouldn't be kept in by wide spaced wires anyway! The perimeter of the enclosure is fitted with downward curving drainpipe halves and the greenery is kept down of course
While the Landscape team do some incredible work, the presentation inside the enclosure is maintained by the Herps Dept. mainly by our wonderful RBS International volunteers this summer actually, who've collectively spent every weekend of the summer maintaining our outdoor enclosures
P.S: You're right though, they don't know the difference! Even I can't tell the difference between pics of truly wild Greens out at St Ouens Sand Dunes or within the enclosure!
They're actually very easy to see, however few people take much time to look properly. The lizards are fairly large, relaxed and prefer to sit out in open areas, they are used to crowds so never run off when people approach.
This is one of our strongest Herp species, conservation efforts across the island to protect various systems ties in and have a positive effect on all of the species we are trying to help.
The Green lizards in the enclosure do breed occaisionally but they are not for rerelease as the previous project for sand lizards was.