Which of these zoos are the easiest and most difficult on public transportation? My friends in the area have given me a lot of information but of course I welcome what zoochatters have to say on this. Being able to reach things via public transport is very important to me as I am not a comfortable driver. (Many of you have already helped a lot with this, but restating in case there is more insight!)
London Zoo - very easy, with plenty of nearby public transport connections.
Whipsnade Zoo - extremely difficult nowadays, unfortunately - the public transport connections which were once in-place have long since been discontinued.
Monkey World - more or less impossible, due to a combination of relatively distant public transport links and dangerous roads between the closest such links and the zoo itself.
Colchester - this is doable by public transport, last I checked - there should still be a direct bus from the railway station to the zoo, I think.
Cotswold - impossible, for the same reasons as Monkey World.
Chester Zoo - very easy, with plenty of public transport options.
Yorkshire Wildlife Park - very easy, thanks to a direct bus running between Doncaster railway station and the zoo.
Hamerton Zoo Park - very doable as long as you have the required stamina - it's quite far from the closest bus stop, but the resulting walk is along a peaceful and fairly safely-walkable country lane, and the bus in question runs regularly from Peterborough railway station - you may be best doing this one during the London segment of your trip, as it's easier to reach Peterborough from there as opposed to Sheffield.
Twycross Zoo - extremely difficult for similar reasons to Whipsnade.
Birmingham Nature Centre - very easy, with regular buses between the city centre and the zoo.