Not a bad idea as it reaches a big audience and is a sure way to attract more visitors, at least short term. These zoo series tend to get made by either the local regional T.V. companies or small Independant ones, but of course only a certain amount of this type of programming gets shown in any year. Nowadays the format is almost always exactly the same, following the keepers on their daily routines, with usually some vetinary work and anything else interesting that's going on during the filming period. For Twycross this might be around a 'crisis' storyline of their current financial and other problems, though they might not want it exposed that they are struggling - it never looks good.
Out of interest, UK animal collections I can think of that have featured in recent years in these T.V. series(ones focusing on a particular zoo that is) include;
London/Whipsnade.
Paignton
Bristol.
Chester.
Colchester
Longleat.
Howletts/Port Lympne(a children's version.)
Dartmoor Wildlife Park.
Manor House Tenby.
And in Ireland; Dublin?
There may be others I can't recall too.
Molly's Zoo, made by the B.B.C. and shown nationaly 1999/2000, five episodes in total, featuring the gorillas, orangs, chimps, bonobos and gibbons with their keepers, there was also video footage of Tara and Karishma being born in 1998. Molly Badham featured in an article in the millennium edition of the Radio Times, entitled "A day in the life of".