Blackwidow, your statement concurs with what I've heard - and that is from the shoe polisher guys in T1.
I wasn't too happy with this. There have been a couple of times when BA/BMI have had to cancel at short notice. It has been possible to quickly transfer across to the other airline and fly to a domestic destination on a Friday evening. I don't rate my chances on a T1<->T5 swap on a Friday PM, it will be quicker to go to London and Kings Cross / Euston.
The shoe polisher was more concerned about the loss of trade due to regular BA domestic commuters leaving as Star Alliance international pax won't be stopping for a polish.
So now he has the challenge of maintaining the business and expanding to T5 - and that's if he's invited to tender.
I'm sure it will all work out OK, but I was quite surprised at the ramifications of the casual question "So, I see BA are to relocate to T5..."