I regret though the ongoing criticism by Gordana's parents that investigators involved in her abduction did not follow up on leads and other levels of information following their daughter's disappearance. Investigators involved in Gordana's disappearance comprised some of the state's leading criminal and scientific investigators who sifted through every piece of information received following her disappearance and for months and even years after. Countless hours of police time rightfully have been expended, but nothing so far has led to any definite evidence as to who was responsible.

At the time of her disappearance in November 1994 I was the Patrol Commander at Charlestown. I can honestly confirm that all available police resources, assistance from SES and hundreds of volunteers were involved in searching for Gordana, sometimes in difficult locations and even to the extent of following up on suggestions from several clairvoyants, clueless as they were.

It is obvious someone knows something which has not been disclosed to date, and I sincerely hope Detective Faber's team of investigators eventually can bring a successful conclusion and finalisation to the mystery of Gordana's disappearance.

THE article recently published stating that the 1786 Beck piano currently undergoing restoration in the United Kingdom was the first to arrive in the colony of New South Wales in 1788, whilst a great good news story, needs to be treated with caution ('First Fleet piano flown to UK for repairs', Herald, 27/3). There is absolutely no substantiated proof, beyond all doubt, that this Beck piano was owned by George Bouchier Worgan, the surgeon on board the Sirius. We do know that Worgan definitely brought a piano with him and left it with Elizabeth Macarthur on his return to England in March 1791. That is well documented through a variety of sources. I believe the principal proponent of the claim this 1786 Beck piano was the first to arrive in the colony, Professor Geoffrey Lancaster of Perth's Edith Cowan University, has based his assertions on the fact it is of the period and has collapsible, cabriole legs, thereby making it easier to store. I understand almost all square pianos of the period were on trestle stands of one sort or another that could be easily disassembled and stored, so merely having a collapsible base is by no means adequate proof to make such a claim. My reading of Lancaster's 2016 publication, The First Fleet Piano: A Musician's View provides many statements casting doubt on this assertion.

To date, no record has come to light stating the maker's name of Worgan's piano. Until such time as that occurs - if ever - readers, journalists and researchers need to keep an open mind on the matter. The search continues.

I AM just wondering if the Adani mine's recent approval is a certainty under Labor since Bill Shorten's promise is to have so many electric cars on the road by 2030.

It seems to me that Mr Shorten has absolutely no idea that electricity is produced by burning coal. We don't have an alternative way of producing enough power at this time that satisfies all our needs domestic or business. Can you imagine waiting in your garage at home or a charging dock and waiting for the off-peak times to charge the vehicle? I think electric cars are a fine idea as long as the infrastructure is in place to support the idea. We all want a greener society, and one day we will have a renewable supply of power. I think Mr Shorten's idea was just a light-bulb moment, but even those require coal-fired power.

IT seems Brad Hill (Short Takes 9/4) has trouble with the idea of 50 per cent. It's the same as half. If Mr Hill thinks of the ALP's policy of 50 per cent new cars being electric by 2030 ('Australia is 'well behind in electric cars take-up', Herald, 9/4) in terms of half, maybe he'll find it easier to understand.

Here it goes: it's a policy aiming for half of new vehicles to be electric by 2030, which means that half won't be electric.

Let's just repeat that last bit to make sure it's clear: half of new vehicles in 2030 won't be electric. Therefore, half of new vehicles in 2030 won't need electric chargers and the electric battery storage he's worried about, nor will any of the non-electric vehicles sold for 11 years before that or any of the non-electric vehicles now on the road that are still going in 2030.

If Mr Hill wants to buy a vehicle that isn't electric, he'll have half of all new cars to choose from plus whatever used non-electric cars that are for sale at the time he wants to buy. I wish him happy caravanning in whatever vehicle he chooses.

I BELIEVE the $185 million expense of re-arming, or refitting, Christmas Island with a defence or deterrent against unwelcome visitors ('PM backs Christmas Island spending', Herald, 8/4) is peanuts compared to doing nothing.

It may be a bluff, but if this bluff can save maybe hundreds of lives at the hands of people smugglers in unseaworthy vessels, l consider it money well spent.

Most would agree in this circumstance that a bluff beats a full hand of going back to places like Manus Island, where the cost in both humanity and money is simply unaffordable. Well done, Prime Minister Scott Morrison, because l believe Bill Shorten would have done the same.

THE arrogance of the federal government, reportedly spending hundreds of thousands of taxpayers' dollars a day on the eve of the election to spruik its budget ('Senators clash over advertising spending', Herald 9/4) which has not even been passed by parliament. I believe taxpayer dollars are better spent providing services to the public, than on advertising for a political party. Wasn't it this mob that told us the age of entitlement was over? Obviously not for them.

THE pen goes to David Crich for his letter about the Knights.