Ah, excellent Matt, thanks.
I'll guess the rear is similar, then.
With my laser display calculator I estimate maximum life (of my particular tortured tyres) to be:
Front: 4k more = 8k overall
Rear: 3k more = 7k overall
Realistically, they'll get changed a little earlier, so we're looking at around 6.5 - 7k for the pair.
In the meantime I'll be breaking much harder, in order to get my money's worth from the front.
My workings (for extra marks):
FRONT:
---------
4.9-3.0 = 1.9mm spent in 4k
So that's 2100 miles per mm
I have 2mm left to legal limit = another 4200 miles left on the front
REAR:
-------
4.9-2.7 = 2.2mm spent in 4k
So that's 1800 miles per mm
I have 1.7mm left to the legal limit = 3090 miles