OOT,
I'd imagine this will be a scrapping of current Apache airframes, spares recovery of those components common to the both versions and new building the AH-64Es. Given that the -64E has new engines and avionics there's probably not an awful lot to be retained. There will, inevitably, be a period as the new aircraft enters service when the "old" aircraft is winding down alongside.
£8m is a ludicrous figure. it might cover the airframe and rotor blades but will not cover the engines, DAS, MTADS/MPNVS and other mission avionics and weapon systems.
Of more interest will be where they are assembled, and by who. Might this be the moment for "Boeing Yeovil"? Sounds better than "Leonardo Helicopters".....