There is an old townhouse on a side corner adjacent to the river Thames in Chelsea, Central London. It had space for two large cars, no gates, opposite an open triangle of road space, and which were in view of the traffic beginning an Eastbound route along the river's north side.
In the Ninetees and Naughties it was owned by a Theatre owning family.
One was a RR or Bentley saloon / sedan, the other maybe a Merc iirc. The cars were nearly always there. Personal Registration Plates.
You guessed it. 2B and N0 T 2B