Not so sure that any revenue traffic will be affected on the NCL-LHR as I think it's two separate markets, although hard to predict.
On a personal note, I liked East Coast (best service we've had since BR) and their little reward scheme; it's come in handy on many an occasion. I'm guessing the northerly commuting VS crew will be delighted though......can't see there being as many red uniforms spotted on the shuttles anymore!!