EGLL Ground freqs.
 

Is there any logic as to what Ground Control freq is appropriate at EGLL, 121.7 or 121.9. Looking at the Jepps along with the UK AIP and I can't tell? North side or South side?

They split gnd into 121.7 and 121.9 because EGLL is so busy. You'll see the demarcation line on the gnd plate (I don't have it infront of me but I think it's on plate 10-9) between Gnd North and Gnd South. Possibly try asking the same question in the ATC forum if this didn't answer it, there are some EGLL ATCOs there that will definitely help.

Thanks for the tip. Will check with the ATC gurus :ok:

Low frequencies are south, except LHR approach.

Works for GMC, TWR, ILS freqs