Liberal MP Sarah Henderson is concerned about renaming an electorate “Cox”

As the first rumblings of election date speculation take hold, the party machines are now finally in a position to plot tactics with a clear sense of what the battlefield will look like.

This follows the Australian Electoral Commission’s publication of new draft boundaries for two states and one territory, each of which will have a substantial bearing on the shape of the election.

Notionally speaking, the Turnbull government has lost its majority without a vote being cast, mostly thanks to the creation of new safe Labor seats in Victoria and the ACT.

On top of the easily quantifiable impacts on party margins and seat shares, the changes will disrupt the major parties by disturbing finely calibrated balances of factional power.

Labor gets one uncomplicated free kick from the new ACT seat, which some creative thinkers suggested could provide Kristina Keneally with a safe berth in the lower house.

On the other side of the fence, this new seat gives conservative revanchists still more to grumble that Malcolm Turnbull and Scott Morrison haven’t cut more deeply into the public service.

The ACT’s seat entitlement has long straddled the boundary between two and three, but only previously tipped over to three at the very end of the Hawke-Keating period – and it shortly went back to two after Howard government cutbacks did their work on the local population.

Even safer for Labor is the new seat of Fraser in Victoria, which will accommodate deep red territory on Melbourne’s growing western fringe.

This outcome was predictable enough that it provided a catalyst for the demise of the “stability pact” between the figureheads of Left and Right in the Victorian ALP, with the Left falling out over a spoil that was pre-emptively allocated to it.

The picture is now further complicated by the determination of Bill Shorten – who is, on top of anything else, the most powerful figure in the Right — to take the seat for himself.

However, this is a better problem to have than that confronting Liberal MPs Chris Crewther, whose south-eastern Melbourne seat of Dunkley will become a notional Labor seat, and Sarah Henderson, who is now lineball in Corangamite.

Corangamite is to be renamed Cox, causing Henderson to complain that a “member for Cox” might inspire schoolboy sniggering, but the change reflects an underlying issue that is of more tangible concern for her.

The name change arises because the lake from which Corangamite is named is to be transferred out of the electorate, part of a long-term process in which the seat has traded declining conservative rural territory for growth areas of outer Geelong and the Surf Coast.

There was better news for the Liberals on Friday when the final seat of draft boundaries was unveiled for South Australia, where the commissioners were required to chop one of the existing 11 seats.

Labor is to be taken down a peg with the abolition of its traditional stronghold of Port Adelaide, though much of its territory is now to be transferred to Hindmarsh, a currently knife-edge seat that will become safe for Labor.

It might be thought the resulting preselection headache would be resolved by the looming retirement of Kate Ellis in neighbouring Adelaide, allowing both Port Adelaide MP Mark Butler and Hindmarsh MP Steve Georganas — one a rising star, the other not so much.

However, both are male and from the Left, whereas the Right expects factional stalwart Ellis to be replaced by one of their own, and gender balance demands her successor be a woman.

One aspirant already in place ticks all the required boxes: Marielle Smith, a former adviser to Ellis who currently holds a position as adviser to Julia Gillard.

It may be that Georganas, whom an unidentified party source quoted in The Australian helpfully described as a “loyal and faithful soldier of the labour movement”, is instead asked to take on the marginal Liberal seat of Boothby, which is set to absorb the southern parts of Hindmarsh.

The draft boundaries are now subject to a period of objections and reconsideration, but it would be an uncommon event if this resulted in more than tinkering and perhaps the odd name change.

It is only when the process is finalised, likely around August, that it will become feasible for the government to go to an election, as the states are constitutionally entitled to the seat shares that have been calculated for them come what may.

That development will add urgency to the already popular parlour game of guessing whether the government will take its chances with an election between September and December, or hold out in wait for an elusive poll recovery until the new year.