Evening Steve.
just then I thought you had a set for sale as I’m after some.
This is not a definitive answer but as far as I know (from memory searching a couple of years ago) the OSS cannot be fully opened with factory roof bars on. I’m sure someone who has a set will confirm shortly.
What I do remember is someone stating that they remove the control panel and unplug the switch just in case they forget that the roof bars are fitted, this accidentally opening the OSS and damaging it.
Hope you’re all ok.
Kind regards,
Tom