If AC or TC 'outer' sectors are pressured for an EAT can't they give a best guess estimate or quote the delay for the aircraft just entering the inner holds as a guide?
I try to do this but we don't get the delays for any aircraft until they go above 20 mins. This "less than 20 mins" rubbish is just pointless it could mean from 0 -19 mins. AC should have a link to the EGLL EATs aswell as the other TMA airfields on the SIS, that way when the delays start creeping up then we can help by slowing stuff down. At the moment we are left guessing by looking at the landing rates and counting the traffic ahead of the one asking. If we chucking stuff in at 300kts + and the delay is 15mins let us know and we'll slow it down. Better communication between TC and AC is the key.
As for the LOGAN hold, using the furthest away, highest level AC hold is not sensible. It should be used as a last resort as it causes so many problems not just for CLN but NOR. LMS, LUS and Maastricht.