A 0500 notice is known as a Revised Duration Estimate.A 0500 is used to amend the Estimated start Date on NRSWA notices (before works starts) or for Permits it is used to agree the reasonable period, without varying the permit end date, following a duration challenge.
If the estimated end date is not updating, then it is likely that the wrong notice type has been used.Check to see if the works is In Progress. If it is then a 0510 notice should have been used.The estimated Start date will only change if the works is not In Progress. A 0500 is used for Permitting when the Permit Authority send a duration Challenge. This notice type is used so the Utility do not work without a valid permit. Sending a 0500 amends that dates in the works form but keeps the original dates on the permit. This means the utility can continue working in the Highway with a valid permit but the Authority can impose S74 overrun charges from the date of the challenge date.