Fascinating stuff, and shows NR is on top of the HS2 requirement at least, to save 10-12 minutes on the PS speed profile of the northern WCML.
It looks like a similar speed profile to EPS is theoretically possible with 75-ish physical interventions on the track alignment (each way), plus 20-odd signage changes.
A price tag of around £100m is quoted, probably to be taken with a large bowlful of salt, and down to HS2 Ltd to fund.
That's for Handsacre-Glasgow, and I would assume Handsacre-Crewe will not actually now be needed if HS2 phase 2a is delivered contemporaneously with Phase 1.
Either way is doesn't consider the southern WCML which is where the 80x requirement is, or who would fund those interventions.
Interestingly, a possible speed profile higher than EPS on some sections is considered, assuming ETCS is implemented.
As Mr Rick says, there are lots of caveats about detailed track design and the constraints of other disciplines (OHLE, signalling, maintenance etc).