Paloma Zozaya Gorostiza

I have followed and enjoyed Last Tango in Halifax enormously, BUT I found the last series which ended last night a big let down. Whay introduce two totally charmless characters like the brother coming back from Australia and the con boy to take time from the strong characters we have been following? Everything was left up in the air, the last chapter given away to the awful con boy driving around with the old guy who only came into the series to take away attention from the two families dramas, then die. I was very disappointed, there was none of the brilliant dialogue and plot of previous series, was the author changed?