Stuart,
I standby my previous statement.
The bases of the Mark I & Mark II are as below

It should be noted that if you place a Mark II phone on a Mark I base it will not fit because of the extra plastic around the pins as shown in the left picture above. However a Mark I phone WILL fit onto a Mark II base.
That is why people think that the new type wall charger was sold with the Mark I, but as far as I am aware it was not.