If it is 20:00UTC then it is 20:00LMT on the Prime Meridian; 0800 LMT at the Prime meridian is wrong.

 

                                        20:00UTC                                   20:00UTC                              20:00UTC

                  060ºEx4m   4:00                    090ºW x 4m  6:00              120ºW x 4m   8:00

                                        24:00LMT X                               14:00LMT p                       12:00 X