Originally Posted by Tits McGhee
To try and get Asiana to check you all the way through to MAN though - aswell as your bags. If they do this and give you a boarding card, just follow the FLIGHT CONNECTIONS signs after immigration and you will find a coach to drive you over the airfield (or under it, atleast) to T1 for your next flight.
And even if Asiana can't give you a BA BP for LHR-MAN, use the FCC if your bags are through-tagged to MAN.
You should note that if you use the FCC, you will clear immigration at the FCC at LHR before going on to the BA domestic area. However, you will technically clear customs at MAN. I don't know how the mechanics of that works there, but your bag tags will clearly identify you as someone who has not yet cleared UK customs.
Originally Posted by MAN Pax
Sorry, Standard only if you are transferring. Though, they may not be round to check your ticket

The usual method of policing this appears to be for the staff to stand at the doors of the first class carriage at T4 saying "First Class to Paddington?" in an intimidating fashion.