Just for something different I've been and done some intervals on the bike,
2.74m warmup then,
4.92m / 400' (16:29)
0.65m recovery (2:16)
4.92m / 400' (16:56)
3.39m warmdown (11:19)
I would have done a third 4.92 mile interval but I went out too late and it had got too dark!