Parking at Heathrow Terminal 3 Short Stay

Have you ever parked a motorhome at terminal 3 heathrow short stay- Height limit -getting contradictory answers via web and phone. I know, there is extra height on ground floor but would be interested if somebody has actually used it, because the web site says one thing and the people on the phone say another. Looking at about 2.800 metres, 8 ft plus ariel.

Any news would be most welcome.

Thanks