Bow Street Runners were nicknamed "Robin Redbreasts" for their uniform red waistcoats, as seen on the man chasing Lady Whistledown's carriage and later on the two Runners in the Featheringtons' front hall.
It's unlikely that Colin Bridgerton would go on the Grand Tour as in the regency era England was at war with Napoleon and the upper class began vacationing to places like Brighton, Bath and the Lake District.
This episode is dedicated to the memory of Brian Nickels. Brian "Sonny" Nickels was a stunt coordinator on the show. Nickels died suddenly in January 2020 from cardiac arrest in London, England.
Around the 24:00 minute mark Daphne says "I'll be down momentarily" in the American English way, as in a short while. The British English uses momentarily as in "for a short period".
Emma Naomi and Ben Miller both appeared in all 6 episodes made to date of the UK version of Professor T.