It's due to the new rules coming in September, which relates to safe guarding issues.
This is why Bucks council are offering English language support for any taxi drivers in the county.
All their help, which includes tutoring and workshops, can be found on here https://www.buckinghamshire.gov.uk/parking-roads-and-transport/taxis-and-private-hire/taxi-licence-applications/english-courses-and-workshops-for-taxi-drivers/?fbclid=IwAR3d-5C25UGF1wHUPhNakb3bpU3C5h0uehwWm5N3xdqEi0tqRZ24cP3KrVw