I've recently put ES Scillies and Alderney on this pc and found I have no vegetation at Alderney.. probably a few other things missing too. I remember something back in the mists of time about there being some sort of conflict which required both areas being uninstalled then Alderney being installed first followed by the Scillies (I installed them the other way round as I have the Scillies on DVD and hadn't made a 'Pack' for Alderney).
I emailed support a week ago and have yet to receive a reply

Rather than uninstall, would it work if I move IoS above Alderney or does the lot have to come off?
ATB
DaveB
