It seems the open land between T5 and the M25 would be least disruptive, it would also interlink nicely with T5. I still feel the R/w could be built the other side of the motorway in relatively open land with just connective taxiways back across the motorway to connect into the main a/p There is no reason why the new terminal has to be closely connected to the new r/w
I am also wondering why freight has to come into Lhr surely a new freight terminal at Lgw would allow it to connect to Europe through the channel tunnel without all the difficult trucking around the M25