Originally Posted by corporate-wage-slave

Welcome to Flyertalk Nev Arthur, welcome in particular to the BA forum. It's good to see you here and I hope we will be able to benefit from your questions and insights in the future too.

As noted, officially it is "no guests" but as far as I know only GVA sticks to that rule, and they are an out-station with a particularly high number of status travellers. Everywhere else you are unlikely to have a problem take a guest or two through Priority Boarding. Fast Track specifically allows 1 guest, as does lounge access.