I'm afraid they've got you there Mark. There are warning signs as you approach Hartington Rd on the A316 and you commited the infringement when you passed the "flying motorcycle" signs just before Cavendish Road when you left the club. The restriction has been in operation for quite a while now and to begin with they were just handing out warning notices, but that grace period seems to have ended. It is a very controversial topic — as you will see on this forum! Have Roko not put up any sort of warning themselves? If not, then they should. You can read about the Hartington Rd and other traffic schemes in what is now called (at least by Hounslow) "South Chiswick". There are plenty more waiting to trap the unwary. https://www.hounslow.gov.uk/info/20053/transport/2181/south_chiswick_liveable_neighbourhood/3