terrain safe, I did say the major London airports
Gonzo, your Pt 2 must be different to ours? Ours says that whilst 3nm may be considered to be the standard final approach spacing, it is incumbent on the tower WM to maximise runway capacity i.e. offer 2.5nm spacing if at all possible (all criteria met).
That doesn't mean we're aiming for 3nm allowing a reduction to 2.5nm if it decreases for any reason. It means we're aiming for 2.5nm from the start and all the way down the approach, but I'm sure you did know that so I'm unsure why you replied as you did?