Hi, as @Helen3 states, contact the council, based upon the Airbnb site, it seems your area has a robust process re: STR, and they most likely can advise you how to proceed forward.
Best to expect your neighbor has reviewed local STR rules/ Airbnb host rules, and has "their" examples of your violations of STR law, parking, noise, neighbor courtesy, illegal activity, etc.
Good thing Airbnb has a very rigorous process for hosting, host vetting, etc...and you can talk all about this, and the quality of your guests. :).
Best to come prepared with records, for example, no calls to police re: noise complaints, no parking tickets for parking violations, no calls to police for illegal activity.
A list of guests (names obscured) and their professions (which you can find on LinkedIn)...
Hopefully, it is a simple fix as someone keeps parking in "my street spot" vs. a litigious neighbor.