Grattan on Friday: The Nationals install a Barnaby whisperer as they pass on the family farm

In some circles they call Fiona Nash the “Barnaby whisperer”. It’s said she’s able to calm him down.

In electing Senator Nash their new deputy, out of a field of seven candidates, the Nationals have acted wisely.

They have installed their first female deputy, a good move when there has been lots of talk about the need to get more women into higher political places. They’ve put in someone who should carry good electoral appeal.

And, perhaps especially important, they have given Joyce an offsider who is likely to make him more effective.

When Joyce has a poor relationship with people it can end in tears, as happened with a former head of his department. If the ballot had installed someone who wasn’t a natural ally, things could have gone awry. Joyce and Nash worked closely when he was a senator, and he has been a supporter of hers.

The role will be a challenge for her, however. She has not been regarded as a particularly strong performer as a portfolio minister. She’s currently Minister for Rural Health but as a cabinet minister she will likely be in a new and more demanding portfolio. She will need to sharpen her policy skills.

After a long, agonising period of speculation about Warren Truss’s future the Nationals, who change leaders rarely, contained the obvious tensions around the transition. In the end, Joyce didn’t face a contest – his putative opponent, Michael McCormack, backed off. The Queensland Nationals, having had the leadership, are angry they couldn’t get the deputyship, but they must know they did not have a credible candidate. On the whole, the Nationals “family” managed to hand the farm to the next generation with some aplomb.

Things were messier on other fronts within the government.

In just the past week, Malcolm Turnbull has walked away from a major tax mix switch and been forced to have his departmental head inquire into whether one of his ministers, Stuart Robert, breached the code of conduct.

Turnbull’s government has attracted some “barnacles” surprisingly quickly, and he’s been busy scraping them off before they corrode the ship.

His ditching of the GST rise, which had been trailed so conspicuously by Treasurer Scott Morrison, disappointed the reforming purists, but Treasury modelling put out by the government on Friday morning shows there was little choice. A switch would produce no growth dividend, according to the modelling, which is broadly backed by similar work commissioned by the government from two private firms.

On these figures, the tax mix switch would be just not saleable - or indeed worthwhile. Turnbull rather danced around issuing the formal death certificate, but Industry Minister Christopher Pyne was blunt on Thursday. “There won’t be a [higher] goods and services tax,” he told Parliament.

Despatching the GST increase clears the decks, but it doesn’t give the government a solid and marketable tax package. There are multiple problems ahead, as the government battles to slice and tighten concessions and find other ways to produce funds for modest income tax relief. A higher GST would have brought an enormous public backlash but even without it there will be plenty of screams from those who lose something in the final package.

When you are trying to deal with this and other difficult and politically sensitive policy conundrums, it is not the ideal time to have to reshuffle your ministry - which has been necessitated by ministerial scandals as well as the Nationals' changeover.

Scandals are always unfortunate for a leader but crucial is how they are handled. Turnbull brought the Mal Brough affair on himself by appointing him when Brough was under a cloud. In contrast, the Prime Minister quickly got rid of Jamie Briggs over his inappropriate behaviour towards a female public servant. Now he needs to act decisively against Robert, and is expected to do so.

The Robert affair cast a sleazy pall over the parliamentary week. It’s obvious that Robert, a big fund raiser for the Liberals, has been all too anxious to please Paul Marks, a generous donor to the party. On private leave, Robert in 2014 was at a signing ceremony in China involving Marks’s company. The year before he organised, at Marks’s behest, a dinner at Parliament House for a wealthy Chinese businessman to meet Tony Abbott, then opposition leader, and other Liberal luminaries (at which the businessman gave out designer watches that the politicians, showing a streak of naivety, wrongly assumed were fake).

The ever-optimistic Turnbull will see the reshuffle as an opportunity, and indeed it is. It’s a chance to get some new talent onto the front bench, and to fine tune the existing team. The elevation of Nash means there is automatically another woman in cabinet.

Turnbull wants the reshuffle done as quickly as possible. The government has recently been looking ragged, and he needs to settle it down.

So far, despite the untidiness and worse, the Turnbull ship has taken relatively little water. The reaction to the shift on the GST, and to the scandals, would have been far worse if they had happened under the former prime minister - or for that matter the one before him.

Politics is about comparisons and Turnbull is lucky – he’s judged against his predecessor, Tony Abbott and his opponent, Bill Shorten and the verdict comes out in his favour.

But there are questions starting to be asked about him – such as what he really stands for and what is he delivering.

He is still being given the benefit of the doubt. But he can’t afford more distractions. The policy work is getting harder and time is running out.