Vespasia,
I reckon our part 2 is similar. I don't have it to hand, but the first one has to be on the deck, and of course you'd have to wait a bit to see the speed under control, although says nothing about 'after the vacating'. Similar criteria to you; 2500m down the runway, or vacated. The few controllers whop use it quite a bit tend to (as I would) give it when the 1st is about half way through it's landing roll, so the next is 1-1.5 miles out.