Heathrow's case for being 'essential' to the North is increasingly flaky. Far from being essential it is now not even very important. It is simply one of many alternative ways to reach the shrinking list of destinations not served direct from Manchester, and not even the most attractive option in many cases. T5 is a nice enough terminal in which to transfer if that is indeed the one on offer. But the connecting flight gives barely time to settle in to your seat, and on a single-class single-aisle aircraft. Not great if you're a premium traveller compared to the wide-body alternatives or the business class product on the EU flag carriers out of MAN
I am not anti-Heathrow, it is good for London and the southeast, essential even, but a third runway is far too expensive and the national case for it does not stack up.