The whole of this debate is nonsense.
Constituencies are to be made larger and less geographically meaningful in an attempt to get the votes to seats ratio more equal between the Tories and Labour. The fact that the Liberal Democrats and others face a huge votes to seats ratio does not seem to matter.
Why is PR which would mean one person, one vote, one value rejected? Is it because PR would make constituencies larger - or because first-past-the-post leads to stable one party governments?
All of these manoeuvres (retaining the present boundaries, limiting electoral reform to AV, changing the number, size and geography of constituencies) are forms of gerrymandering.