anyone had experience of using a tag device to pay for tolls on severn bridge or in france ? the same company operates both systems.
The tag itself needs to be fixed to a non metallic part of the windscreen which I think is the spotty part around the rear view mirror?

I used the SANEF tag for tolls driving through France, worked perfectly (albeit on an XF, but it did have heated windcreen).

It ONLY works in France, not other countries, and I don't believe it would also work for the Severn or Dartford crossings.

Fitted up by the rear view mirror mount. MY2016 HSE D SDV6 - gone due to fuel dilution problems.

By the age of 50 you have the face you deserve - George Orwell.

I have used it in France, stuck on the spotty part of the windscreen behind rear view mirror but in L320. Seems you want to know specifically for L494. Current: Volvo XC90 T8 Inscription Pro PHEV with some optionals on top
Gone: MY16 RRS2 3.0 SDV6 Autobiography Dynamic, Carpathian Grey & Santorini Black Sliding Pano/Ebony & Ivory 2 Tone
Gone: MY13 RRS 3.0 SDV6 HSE Black Edition, Orkney Grey/Ivory
Gone: MY09 RRS 2.7 TDV6 HSE, Santorini Black/Almond

just returned from france & it worked perfectly. I mounted it as per instructions on the black area next to mirror. Eurotunnel were doing a special offer on them, don't know if this is still current.
As for the Dartford crossing it struck me as that now there are no toll booths or barriers and you are required to purchase a ticket on line, as per congestion charge, foreign reg vehicles go free.

Thanks pko, was a bit concerned as no spotty area only a black bit so glad it works, have a French tag from a eurotunnel deal a few years ago, same company do the Severn bridge so hopefully the mount will be the same ?!!