when unlocking car with one remote and drive off the doors dont lock and never has done with this certain remote however when i use my spare remote the doors auto lock after 5mph and always has done with this one. how can i reprogram the first remote to stop door auto locking, seems odd one auto locks and the other does not.

using the key you have the problem with,
turn the ignition on
press the i button on the end of the indicator stalk, untill it says SETTINGS

then follow on screen instructions !, using the steering wheel buttons << >>

As Andy K says, you need to set it for each key. The system remembers the keys individually - so that two people can use the same vehicle and have their own preferences remembered. Quite a good idea for those that share a vehicle. 2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

A good idea.

But in practice, annoying

Annoying if you just pick up either key, less of a problem if you each have your own key.

I just use the one key with the other a spare so I've never really bothered with the function.  2012 SDV6 - it's missing a couple of cylinders
2008 TDV8 - it was a labour of love and is much missed

Thanks gentleman, all sweet now, did it through the menu as you guys advised.