New Car -Missed DARTFord crossing payment by 48 hours

Hi All,
I missed my Dartford crossing payment by 48 hours as I did not realise that the new lease car was not registered in  the Dartford crossing portal(Vehicle Management). I am still not able to see the crossings transaction I the portal.

Any guidance that you could provide to avert the PCN ?

Sorry, but have you got a PCN or not ? Sometimes it is of benefit to contact DART to explain what has happened. They are not bad to deal with, unlike London councils, so may just request payment of the unpaid toll. Clearly you were expecting auto-payment to carry on with your leased car, and not trying to avoid payment.