More likely that Sergei decided to go home due to covid, and has decided not to return, so has sold the business on.
Admiral always used to have the most girls on its books of all the agencies I was aware of, which suggested they weren't particularly discerning. A couple of girls I used to visit weren't very complimentary about them, saying they pressured girls into accepting bookings they would rather not, and recommended I book them via other agencies. Their receptionists were also often quite brusque and unhelpful. So they were always the agency of last resort as far as I was concerned. Will have to see if things change with the new owners.