He has now simply re-stated that his diagram is not "on the wrong side of the RCD", but has not explained why, - so perhaps I can help you understand waht he was illustrating......
.... the 'load' he is showing is that on 'other circuits' (other than the one protracted by the RCD he shows) or, as he says, possibly even other properties/installations - and therefore is on the 'supply side' as far as the RCD shown ( which may trip as a result of an N-E fault) is concerned.
His was a variant on the diagram usually used to explain to people how an RCD can trip in response to an N-E 'fault' (usually due to people touching conductors together with only SP 'isolation') even when there are no loads on circuits protected by the RCD in question - loads on other circuits, or even 'next door'can facilitate a trip in response to an N-E fault.
