Oops!
Bral I take it your on the 146. I was only trying to fill in a few gaps so that what we know might be known elsewhere, I wasn't trying to be pompous. I forgot about the 146 and so, it seems, has everyone else!!!!
The answer to this on reflection may be that it is a line in the sand and the statement is referring to a/c currently flying on routes that are crewed NOW by BA mainline crews. Just a thought.