DELL Laptop Docking station/Graphics Issues

Good afternoon everyone!

Here's the issue:
Our company generally uses DELL D430 laptops (nothing complicated or advanced) with the standard DELL docking station connected to the usual monitor, keyboard etc.

Some of the users have run into the recent issue that when they close lids and put the laptop on the docking station, the monitor does not automatically switch over. In fact, it is almost as if the monitor no longer works (occasionally does with a combo of Fn + F7 and various resolution settings. The following measure worked temporarily, until the user came back after the weekend 'having done nothing' and we went back to square one....

I reinstalled all graphics drivers, and then in the hardware profiles, deleted the 'docked' H/W profile. For 30 mins whilst i was testing after, there was absolutely no problem.

I have been in contact with DELL and they are 'researching the problem'. So I turn to my more reliable sources on the forums....

Any more ideas on what could be done? Any more information you need? Let me know... thanks! :-)

P.S. All laptops are identical spec... some have the issue, some don't. There is no obvious link between users who have it and those who don't.

yeah... all drivers have the most up to date drivers. I even tried with a rollback to older versions but no joy.