Think you will find that fresh concrete is the extensions to either end of the South Stands that was completed a year or so ago that added 2 new stands. I also think a narrow strip of grass still separates Taxiway Delta from the South Stands but I will check it.
From memory taxiway Foxtrot is the parallel taxiway to Delta that is under construction. Taxiway Golf will replace holding point A1 which will be moved to the taxiway extension at the 26 end that has yet to be built.
Going back to the parallel taxiway Foxtrot, there will be a second connection to Delta half way along it so will that short link become taxiway Juliet? Not sure if the letter i is used for taxiways.
Just as a side note holding point F1 already exists which is the entrance to the Harrods hangar apron so will that be numbered K1?