VIC Conflicting speeds Signs

[What-da]

Hi All

I was driving through Melbourne city link tunnel, when I entered the tunnel speed sign were displaying 60km with yellow flashing dots.
I preceded to drive through the tunnel at 60kmh and at the 90% of the tunnel there was a road safety vehicle displaying 80km 1.5m tall large Regulatory signs I believed this was the end of road work and started to travel at a new speed limit.
I received a camera infringement notice and now going to court to appeal it. I was wondering how I should approach the court with this and is there any laws that I should look into about two conflicting signs. Thank you in advance.
Thank you in advance.

 

[Scruff]

Revenue raising at it's best. In my view, the 80km/h sign should have been covered, but that's not a requirement.

The fact is that once you enter roadworks with a reduced speed limit, that limit stays in force until you reach a sign displaying "end of works" or similar, not another speed limit sign. For that reason, I don't think you'll get anywhere by challenging this one.