Season 1 of the channel five documentary zoo days is now available to view for free on youtube. YouTube - Zoo Days
Zoo Days was 3 series from Chester and 1 from Colchester. ITV are showing a series about London and Whipsnade in the autumn.
FWIW there are five series of Zoo Days on SeeSaw, three from Chester, two from Colchester. Use the "More" button to find the fifth.