Thanks T21, minor problem is I'm in DXB at present but I'll call the local office.
After posting I checked some other routes like Glasgow - Munich and Edinburgh - Milan via BRS on the BA booking system & BRS doesn't show as a option whilst it does on the desktop. Certainly doesn't encourage then use of BRS (and therefore more services therefrom).
Makes me wonder how much, if any, connecting traffic there is over BRS on BA. Surely it could take some pressure off LHR which would be to BA's advantage opening a few slots more for longhaul. OK not necessarily right now, but in the longer term.
Thanks for the info anyway, you've given more info in an hour than I got in 3 emails over 3 days from BA.