Have the union played a blinder??

[parforthewalk]

At that point they might start looking to sell the letters division or franchise it off so they get it off their hands.

There's legislation preventing them from doing that though. Its called the universal service obligation which they have wanted to get rid of for years.

But if delivering letters is that unprofitable now, who else is going to buy it?

No one

But you're right,they do want rid of it so they can become a glorified courier company.

Yes agree with that, you only have to look at failed TNT/whistl model.
They couldn't make it work delivering letters only 3 days a week with no rural element!