They are most likely fussy about everything else too- I'm not suggesting it's just the lime putting everything right, but certainly a higher than necessary pH is doing them no harm. I have grass growers that want pH values up at 7 too, and they can grow some serious grass, I can tell you.
£200/ac+ FBTs, fancy new drills, SDHIs perhaps leaves no £££ for say a tenner a year in the pot for rotational liming. False economy.
The view that land over 7 ph needs no lime is I think quite wrong. What is the calcium offtake of a crop of wheat? Lime is fertiliser too - if I can spend £££ on molybdenum, I can afford some lime.
I know I am not a big DD'er (yet), but I am liming my high pH clays, and will certainly be taking the straw off before the rape this year. And if conditions don't allow, I just wont be drilling - all thoughts of rotations and having a shedful of seed can go to hell if it pours down again. Wet clay is bad. We chopped straw is bad. Putting a little seed in wet clay and wet straw? No thanks.