We've always found the zoo an enjoyable day out but found it looked tired and unloved with lots of the foliage overgrown out to walk ways. We saw lots of animal activity which was fantastic, although we missed the lions which are almost at the end of the one way system, but was the talking point from the time we got in the gate from our 4yo.
We were in for a 4.30pm slot and the disadvantage of the one way system was that everyone was in at the same time going in the one direction so social distancing and viewing was difficult. Also the food outlets were mostly closed despite still being busy with people about, so go prepared and pack a picnic and snacks. Also the play areas closed which I think has more to do with getting you in and out in a timely manner rather than Covid as all playground have been open for months.