Similar issues will happen on some North West routes. 195s/331s, 350s, Sprinters, 319s/769s, Voyagers/Pendolinos all running round with completely different couplers. Progress eh.
Is daft I agree, but a pendo and voyager can couple mechanically. However you need a degree and patience of many saints to do it. And ideally a quiet railway (!) .Maybe it's time for NR to bite the bullet and insist on the same couplers for all stock.