On the settlement, BA is clearly in no hurry to expedite a resolution.
In part, I think BA wants to keep the moral high ground and will not use the often quoted 90 days notice to force a resolution and will want to clear resolution through an agreed settlement.
Ultimately, it will know the impact of the strike threat on forward bookings and market share (its own figures show that bookings recover sharply once a strike has passed) and on the company's reputation and brand through tracking surveys etc. The traffic figures for the past couple of months have shown a good recovery in year on year numbers and yields are also improving. It also has plenty of other things to getting on with (Iberia merger, TATL ATI etc).
The company also has the costs savings it was looking to achieve and it has been able to introduce Mixed Fleet at LHR on entirely its own terms. This would have been absolutely unthinkable a few years ago.
BA is not really losing much at the moment from there being no settlement (indeed it doesn't have to give the pay rises to union members in the offer).
I don't believe DH has any intent to settle this dispute, he gains nothing from doing so and whatever moves BA makes there will always be something else to add to the list of grievances.