Andy, 10miles the day after a half marathon isn't a short one to anyone on this thread....but clearly as you're doing upto 40miles a week more than the highest on this thread, it's a different scenario all together!
100+ miles a week is a hell of an outlay...
It's a bizarre dual world I live in. The guys at work think I'm some kind of amazing training animal..yet in reality they don't know the half of what my training involves.
Then I come on here, and it's like wow...there are some true extreme trainers out there 
ps...as UG hasn't posted for a while, I'm sure he won't mind me quoting a session I spotted he'd done.
17x1100 at 3.44 a rep off 90secs.
So that'd be a mere 11miles or so at 5.25ish average pace.
Standard. 