The right turn from Regent St to Conduit St was blocked a few weeks ago, as the C2 towards Victoria was on diversion via Hannover Sq and St. George's St. Conduit St was one-way north-eastwards. The TfL live travel news shows that buses are subject to diversion until approximately Sunday 29 June due to utility works at the junction of Conduit Street and Regent Street. The route in the other direction is not affected, so I guess the one-way set up is still in place.
Suggest putting in a one-way restriction to prevent Waze routing south-west along Conduit St until 30th June. Apologies that I didn't do anything at the time but I don't Waze on a bus and I was well lubricated after a celebratory dinner at Efe 2 in Gt Portland St
[Off-topic, but if you like lots of meat in your meal, their mixed kebab was wonderful!]