A full test kit is required:

• Two pole approved voltage tester.
• Voltage tester proving unit.
• Non-contact voltage indicator..
• A single pole contact voltage indicator that can be used whilst wearing PPE.

https://martindale-electric.co.uk/product/smkit5-smart-meter-installation-kit/

They can be bought as a kit or as I did individually. Having worked on some scary installations, I have acquired a selection of voltage testers, I have encountered reserved polarity on the meter tails and within the installation, but never on the DNO network.

A genuine picture of the front seat in my van, these are additional items to those in my tool bag which includes two Fluke T150 voltage testers which give a single pole voltage indication and other lock offs.

Fluke T150 with the batteries out and in, as well as batteries in but only single pole contact, there’s audible warnings as well with the batteries in and the option for a low impedance tests which gives visual, audible and tactile warnings as it vibrates as well as buzzing and lighting up.

The tip shrouds were only removed for those particular tests and have been refitted.

I wonder how well the single pole/non-contact voltage indicators would work in an installation  where main bonding connected the metallic structure of the building to the supply L (normally PEN, but reversed). If I understand correctly, they use stray capacitance between the user and the rest of the world to complete the circuit - but if the surrounding world is at 230V rather than 0V wouldn't we be back in the same situation as for conventional 2-pole testers?

   - Andy.

Surely if you earth the incoming live there will be a big flash and lots of smoke as the earth lead burns up also after all you would get current of hundreds of amps just briefly until your earthing and or bonding conductors burn up. I cannot imagine it's a situation that could last long

I did consider that, but then also tried to envisage an extraneous conductive part free situation, perhaps a house with no metallic services... and in this situation could a PME Line/ PEN reversal remain on the installation supply, prior to installation energisation?

Depends what you mean by Earth - short to the DNO's Earth terminal, yes. Connect to a local electrode - probably not - more likely a few amps flow....

In the OP's suggested case it's only a reversal of the L and PEN conductors - no short as such (unless there's bonding to extraneous-conductive-parts that are metallic though to another installation, where they're bonded to a correctly polarised supply from the same transformer, in which case, yes flash and bang again).

    - Andy.

Some installation testers have a single pole test built into them as well.

youtu.be/HyzlpD66EW0

I see what you mean.

I would like to think that the DNOs have a means of confirming correct polarity, but I have struggled to find anything online.

It may not be the advertised process but a wire to any outdoor electrode of opportunity (water pipes, lamp post to the meter probe into the mud, to pry bar or larger screwdriver in the lawn) has been seen being used by the local chaps round here. That and the tip  of a knife to pinprick into the insulation of the cable and then a connection to the knife...

In tight situations when things feel off, folk get inventive quite quickly and SSE are no exception. To be fair the stabbed cable was taped up with self amalgamating tape afterwards, and replaced once the final repair was made.

Actually even the few mm of exposed metal on the  probe tips a digital volt meter makes a good enough "earth" to indicate a few more volts than expected, which is all that is needed to trigger the 'something's up' alert that leads to double checking, It may be an electrode resistance of 10kOhm but the meter still shows there may be dragons.

Mike