Clock should be automatic from the RDS signal.

But don't relay on anything Classic FM transmit, their time-code is all
over the place!

Right, just checked my full radio manual, clock setting is buried in the
expert mode menu (not covered in that link above).

Press EXP for 3 seconds > EXPERT on display
Use up / down arrow button to select menu function
Time comes up as e.g. "TM 2:13"
  station button 2 = hours-
                 3 = hours+
                 4 = mins-
                 5 = mins+

To start clock, press EXP briefly.
RDS sycronisation  shows as "SYNC ON" or "SYNC OFF" as next item in
expert menu. Station button 5 = on, 4 = off.

Press EXP for 3 seconds to exit expert mode

HTH