"Which Beckhampton Avenue do we re-build"?
Hi NightGirl.The question of 'to which period' or, 'how much' do we restore something is a question asked by conservators and restorers all over the world on a daily basis. Surprisingly (and disregarding any financial constraints) it usually comes down to two things - common sense and the record of how an object or site was before it was damaged or dramatically changed.
The argument for the conservation and restoration of the Avebury Henge is outlined here if you're interested - http://heritageaction.wordpress.com/2009/04/15/aveburys-restoration-and-the-stukeley-line/