Posted: 12/07/2012 at 13:27
It is all about editing and pre-production-If you allow say roughly 20 minutes in Monty's garden then they probably film around 2 hours,then you have to allow for setting up cameras, lighting, sound, perhaps re-shooting things for technical reasons or outside noise etc-that that has to be edited down to fill the allotted time
All this takes time and it is obviously done in post production
Secondly there may be other commitments that a presenter has be they private or professional-we don't know.
I am sure there are many reasons why it is filmed a week ahead-at the end of the day it is just a week and don't see that it matters that much