I have just taken delivery of a new superb elegance estate and I am finding the double klick key most annoying especially when my wife wants to open the tailgate and I have to remove the key from the ignition to unlock does anyone know how to allow the key to unlock all the doors together?

You should be able to set this in the maxidot (see page 45 and 52 in the user guide). Select comfort - central locking. At a guess, you probably want to disable "single door" and "one side" to always unlock everything.

You can also use the unlock button on the driver/passenger door. This will unlock everything when you're inside the car without you needing to remove the key. If you turn off the auto locking option, again in the maxiot display, the doors won't relock when you go over 20ish km/h, so what was unlocked will stay unlocked if that's more like what you're after.

I can confirm that you can do this in the Maxidot mine did the same, I now have it open with a single press.. 

 

If I remember correct you remove the tick from the either of the first two options in the attached picture...