array(3) {
  ["London"] => array(3) {
    [26] => array(2) {
      [0] => string(17) "1st December 2018"
      [1] => string(14) "21st June 2018"
    }
    [25] => array(3) {
      [0] => string(17) "18th January 2018"
      [1] => string(18) "15th November 2018"
      [2] => string(15) "22nd March 2018"
    }
    [24] => array(3) {
      [0] => string(17) "31st January 2018"
      [1] => string(19) "20th September 2018"
      [2] => string(17) "25th January 2018"
    }
  }
  ["Melbourne"] => array(3) {
    [24] => array(1) {
      [0] => string(14) "19th July 2018"
    }
    [26] => array(1) {
      [0] => string(14) "5th April 2018"
    }
    [25] => array(1) {
      [0] => string(17) "9th November 2017"
    }
  }
  ["Dublin"] => array(2) {
    [24] => array(1) {
      [0] => string(16) "9th October 2018"
    }
    [26] => array(1) {
      [0] => string(14) "12th June 2018"
    }
  }
}

26                  25                  24

London      1st December 2018   18th January 2018   31st January 2018
London            -             15th November 2018  20th September 2018
London      21st June 2018      22nd March 2018     25th January 2018
Melbourne   19th July 2018      5th April 2018      9th October 2018
Dublin      9th October 2018    12th June 2018