Consent
Consent may be sensible where the work is straightforward, you understand what is proposed and any practical protections you need can be agreed directly.
Dissent
For party-structure and excavation notices, dissent engages the statutory dispute procedure. It may be appropriate where important matters require determination, protection or formal regulation. Section 1 notices require separate consideration: withholding consent to a new wall astride the boundary prevents that wall being built astride under the Act; silence about a wall wholly on the building owner’s land does not automatically create a deemed dispute.
Dissent does not mean opposition
You can dissent while fully accepting that the building work should proceed. The purpose may simply be to put a proper statutory framework around it.
Do not decide from fear alone
Consider the actual work, information supplied, proposed surveyor and risks to your property rather than assuming that more procedure always means more protection.
The right choice depends on what you need from the process, not on whether you approve of your neighbour’s project.