Am I mistaken or was this filmed in Hornimans Gardens?
Definitely Horniman and even more obvious in the TV version.
Yup that’s where I saw it but was on Prime so couldn’t rewind to check. 
Yes! My son and I stopped and watched for a while on our way home from school. Amazing how they got the timing right and they coordinated so many people when the gardens were open and people like us were gawping!